<PAGE>

                                                                     EXHIBIT 4.6

                                                                  EXECUTION COPY

================================================================================

                          REGISTRATION RIGHTS AGREEMENT

                                  BY AND AMONG

                         WESTPORT RESOURCES CORPORATION

                              ERI INVESTMENTS, INC.

                               WESTPORT ENERGY LLC

                               MEDICOR FOUNDATION

                                       AND

                        CERTAIN STOCKHOLDERS NAMED HEREIN

                           DATED AS OF OCTOBER 1, 2003

================================================================================

<PAGE>

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                             PAGE
                                                                                             ----
<S>                                                                                          <C>
ARTICLE I DEFINITIONS...................................................................       1

     Section 1.1.      Definitions......................................................       1

ARTICLE II REPRESENTATIONS AND WARRANTIES...............................................       4

     Section 2.1.      Representations and Warranties of the Company....................       4
     Section 2.2.      Representations and Warranties of Medicor........................       4
     Section 2.3.      Representations and Warranties of ERI............................       5
     Section 2.4.      Representations and Warranties of the Belfer Group...............       5

ARTICLE III REGISTRATION RIGHTS.........................................................       6

     Section 3.1.      Demand Registrations.............................................       6
     Section 3.2.      Piggyback Registrations..........................................       9
     Section 3.3.      Holdback Agreements..............................................      10
     Section 3.4.      Registration Procedures..........................................      11
     Section 3.5.      Registration Expenses............................................      14
     Section 3.6.      Indemnification..................................................      14
     Section 3.7.      Participation in Underwritten Registrations......................      16
     Section 3.8.      Current Public Information.......................................      16
     Section 3.9.      Cooperation......................................................      17

ARTICLE IV GENERAL PROVISIONS...........................................................      17

     Section 4.1.      Notices..........................................................      17
     Section 4.2.      Assignment; Binding Effect; Benefit..............................      19
     Section 4.3.      Entire Agreement.................................................      20
     Section 4.4.      Amendment........................................................      20
     Section 4.5.      Governing Law; Jurisdiction......................................      20
     Section 4.6.      Counterparts.....................................................      20
     Section 4.7.      Headings.........................................................      20
     Section 4.8.      Interpretation...................................................      21
     Section 4.9.      Incorporation of Exhibits and Schedules..........................      21
     Section 4.10.     Severability.....................................................      21
     Section 4.11.     Enforcement of Agreement.........................................      21
     Section 4.12.     Confidentiality..................................................      21
     Section 4.13.     Effectiveness; Termination.......................................      21
     Section 4.14.     Belfer Group Representative......................................      22
     Section 4.15.     Medicor Group Representative.....................................      22
</TABLE>

                                       -i-

<PAGE>

                          REGISTRATION RIGHTS AGREEMENT

         This REGISTRATION RIGHTS AGREEMENT, dated as of October 1, 2003 (this
"Agreement"), is entered into by and among Westport Resources Corporation, a
Nevada corporation ("Westport" or the "Company"), Westport Energy LLC, a
Delaware limited liability company ("WELLC"), ERI Investments, Inc., a Delaware
corporation ("ERI"), Medicor Foundation, a Liechtenstein foundation, formed
pursuant to the Liechtenstein Persons and Companies Act ("Medicor," and together
with WELLC, the "Medicor Group") and the persons and entities named on Exhibit A
(each such person or entity, a "Belfer Person," and collectively, the "Belfer
Group").

         WHEREAS, the Company, ERI, WELLC, Medicor, the Belfer Group and certain
other stockholders are parties to that certain Third Amended and Restated
Shareholders Agreement, dated as of February 14, 2003 (the "Shareholders
Agreement"); and

         WHEREAS, the parties to the Shareholders Agreement desire to terminate
the Shareholders Agreement in its entirety and, simultaneously with its
termination, the Company, ERI, WELLC, Medicor and the Belfer Group desire to
enter into this Agreement providing for, among other things, certain
registration rights applicable to the ERI Parties, the Medicor Parties and the
Belfer Parties.

         NOW, THEREFORE, in consideration of the foregoing, and of the
representations, warranties, covenants and agreements contained herein, and for
other good and valuable consideration, the receipt and sufficiency of which are
hereby acknowledged, the parties hereto, intending to be legally bound, hereby
agree as follows:

                                   ARTICLE I
                                  DEFINITIONS

         Section 1.1.      Definitions.

         "Affiliate" shall have the meaning set forth in Rule 12b-2 of the
regulations promulgated under the Exchange Act.

         "Agreement" shall have the meaning set forth in the preamble to this
Agreement.

         "Belfer Group" shall have the meaning set forth in the preamble to this
Agreement.

         "Belfer Group Representative" shall have the meaning set forth in
Section 4.14.

         "Belfer Parties" shall mean the Belfer Group and their Permitted
Transferees.

         "Belfer Person" shall mean any Person included in the Belfer Group.

         "Board of Directors" shall mean the board of directors of the Company.

                                       1
<PAGE>

         "Commission" shall mean the Securities and Exchange Commission or any
other Federal agency at the time administering the Securities Act.

         "Common Stock" shall mean the common stock of the Company, par value
$.01 per share, now or hereafter authorized to be issued.

         "Company" shall have the meaning set forth in the preamble to this
Agreement.

         "Demand Registrations" shall have the meaning set forth in Section
3.l(a).

         "Director" shall mean a member of the Board of Directors.

         "Effective Date" shall have the meaning set forth in Section 4.13 of
this Agreement.

         "ERI" shall have the meaning set forth in the preamble to this
Agreement.

         "ERI Parties" shall mean ERI and its Permitted Transferees.

         "Exchange Act" shall mean the Securities Exchange Act of 1934, as
amended, and the rules and regulations of the Commission thereunder, all as the
same shall be in effect at the time.

         "Medicor" shall have the meaning set forth in the preamble to this
Agreement.

         "Medicor Group" shall have the meaning set forth in the preamble to
this Agreement.

         "Medicor Group Representative" shall have the meaning set forth in
Section 4.15.

         "Medicor Parties" shall mean the Medicor Group and their Permitted
Transferees.

         "Medicor Person" shall mean any Person included in the Medicor Group.

         "Permitted Transferees" shall mean in the case of the Medicor Parties:
(A) a Medicor Person, any spouse, issue, parent or relatives of the Medicor
Parties, or (i) trusts for the benefit of any of such Persons, (ii) entities
controlling or controlled by any of such Persons and (iii) in the event of the
death of any such individual person, heirs or testamentary legatees of such
person, in each case to whom a Medicor Party has transferred its Shares and who
has agreed in writing to be bound by the terms of this Agreement, and (B) any
Subsidiary or Affiliate of the Medicor Group to which a Medicor Party has
transferred its Shares and which has agreed in writing to be bound by the terms
of this Agreement; in the case of the ERI Parties: (A) ERI, any spouse, issue,
parent or relatives of the ERI Parties, or (i) trusts for the benefit of any of
such Persons, (ii) entities controlling or controlled by any of such Persons and
(iii) in the event of the death of any such individual person, heirs or
testamentary legatees of such person, in each case to whom an ERI Party has
transferred its Shares and who has agreed in writing to be bound by the terms of
this Agreement, and (B) any Subsidiary or Affiliate of ERI to which an ERI Party
has transferred its Shares and which has agreed in writing to be bound by the
terms of this Agreement; and in the case of the Belfer Parties: a Belfer Person,
any spouse, issue, parent or relatives of the Belfer Parties, or (i) trusts for
the benefit of any of such Persons, (ii) entities controlling or controlled by

                                       2
<PAGE>

any of such Persons and (iii) in the event of the death of any such individual
person, heirs or testamentary legatees of such person, in each case to whom a
Belfer Party has transferred its Shares and who has agreed in writing to be
bound by the terms of this Agreement;

         "Person" shall mean any natural person, corporation, partnership,
limited liability company, firm, association, trust, government, governmental
agency or other entity, whether acting in an individual, fiduciary or other
capacity.

         "Piggyback Registration" shall have the meaning set forth in Section
3.2(a).

         "Registrable Securities" shall mean (i) any shares of Common Stock
owned by, or otherwise hereafter acquired by, the Medicor Parties, the ERI
Parties or the Belfer Parties, and (ii) any securities issued as a dividend on
or other distribution with respect to or in exchange, replacement or in
subdivision of, any such Common Stock. As to any particular Registrable
Securities, such securities shall cease to be Registrable Securities when (A) a
registration statement with respect to the sale of such securities shall have
been declared effective under the Securities Act and such securities shall have
been disposed of in accordance with such registration statement, or (B) such
securities shall have been sold (other than in a privately negotiated sale)
pursuant to Rule 144 (or any successor provision) under the Securities Act.

         "Registration Expenses" shall have the meaning set forth in Section
3.5(a).

         "Securities Act" shall mean the Securities Act of 1933, as amended, and
the rules and regulations of the Commission thereunder, as the same shall be in
effect at the time.

         "Shareholder Party" or "Shareholder Parties" shall mean ERI, the
Medicor Group and/or the Belfer Group, as applicable.

         "Shareholders Agreement" shall have the meaning set forth in the
preamble to this Agreement.

         "Shares" shall mean shares of Common Stock.

         "Shelf Offering" shall have the meaning given in Section 3.1(c)(6).

         "Shelf Registration Statement" shall have the meaning given in Section
3.1(c)(6).

         "Short-Form Registrations" shall have the meaning set forth in Section
3.l(a).

         "Subsidiary" of any Person shall mean any corporation or other legal
entity of which such Person (either alone or through or together with any other
Subsidiary) owns, directly or indirectly, 50% or more of the stock or other
equity interests, the holders of which are generally entitled to vote for the
election of the board of directors or other governing body of such corporation
or other legal entity.

         "Transfer" shall mean to sell, transfer, assign, pledge or otherwise
dispose.

                                       3
<PAGE>

         "underwriter" shall mean nationally recognized investment banking firm
with experience serving as lead managing underwriter for public offerings of the
stock of companies engaged in the exploration, development and production of oil
and natural gas.

         "WELLC" shall have the meaning set forth in the preamble to this
Agreement.

         "Westport" shall have the meaning set forth in the preamble to this
Agreement.

                                   ARTICLE II
                         REPRESENTATIONS AND WARRANTIES

         Section 2.1.      Representations and Warranties of the Company. The
Company hereby represents and warrants to the other parties hereto as follows:
The Company has all requisite corporate power and authority to enter into this
Agreement and to consummate the transactions contemplated hereby. The execution
and delivery by the Company of this Agreement, and the consummation by the
Company of the transactions contemplated hereby, have been duly authorized by
all necessary corporate action on the part of the Company. This Agreement has
been duly executed and delivered by the Company and constitutes a valid and
binding obligation of the Company enforceable against the Company in accordance
with its terms. No consent, approval, order or authorization of, or
registration, declaration or filing with, any court, administrative agency or
commission or other governmental authority or instrumentality, domestic or
foreign, is required by, or with respect to, the Company in connection with the
execution and delivery of this Agreement by the Company or the consummation by
the Company of the transactions contemplated hereby. The execution and delivery
of this Agreement by the Company and the consummation of the transactions
contemplated hereby by the Company does not conflict with, or result in a breach
of, any law or regulation of any governmental authority applicable to the
Company or any material agreement to which the Company is a party.

         Section 2.2.      Representations and Warranties of Medicor. Each
Medicor Person hereby severally and not jointly represents and warrants to the
other parties hereto as follows:

                  (a)      Authority. Each Medicor Person has all requisite
corporate or other power and authority to enter into this Agreement and to
consummate the transactions contemplated hereby. The execution and delivery by
such Medicor Person of this Agreement, and the consummation by such Medicor
Person of the transactions contemplated hereby, have been duly authorized by all
necessary corporate or other action on the part of such Medicor Person. This
Agreement has been duly executed and delivered by such Medicor Person and
constitutes a valid and binding obligation of such Medicor Person enforceable
against such Medicor Person in accordance with its terms. No consent, approval,
order or authorization of, or registration, declaration or filing (other than
the filing of an appropriate amendment to Schedule 13D in connection with the
transactions contemplated by this Agreement) with, any court, administrative
agency or commission or other governmental authority or instrumentality,
domestic or foreign, is required by, or with respect to, such Medicor Person in
connection with the execution and delivery of this Agreement by such Medicor
Person or the consummation by such Medicor Person of the transactions
contemplated hereby. The execution and delivery of this Agreement by such
Medicor Person and the consummation by such Medicor Person of the transactions

                                       4
<PAGE>

contemplated hereby by it do not conflict with, or result in a breach of, any
law or regulation of any governmental authority applicable to such Medicor
Person or any material agreement to which such Medicor Person is a party.

                  (b)      Shares. Schedule 2.2 sets forth the ownership of the
Shares held by each Medicor Person as of the date hereof.

         Section 2.3.      Representations and Warranties of ERI. ERI hereby
represents and warrants to the other parties hereto as follows:

                  (a)      Authority. Each of the ERI Parties has all requisite
corporate or other power and authority to enter into this Agreement and to
consummate the transactions contemplated hereby. The execution and delivery by
the ERI Parties of this Agreement and the consummation by the ERI Parties of the
transactions contemplated hereby have been duly authorized by all necessary
corporate or other action on the part of each of the ERI Parties. This Agreement
has been duly executed and delivered by each of the ERI Parties and constitutes
a valid and binding obligation of each of the ERI Parties enforceable against
each of the ERI Parties in accordance with its terms. No consent, approval,
order or authorization of, or registration, declaration or filing (other than
the filing of an appropriate amendment to Schedule 13D in connection with the
transactions contemplated by this Agreement) with, any court, administrative
agency or commission or other governmental authority or instrumentality,
domestic or foreign, is required by, or with respect to, any of the ERI Parties
in connection with the execution and delivery of this Agreement by the ERI
Parties or the consummation by each of the ERI Parties of the transactions
contemplated hereby. The execution and delivery by the ERI Parties of this
Agreement and the consummation by the ERI Parties of the transactions
contemplated hereby do not conflict with, or result in a breach of, any law or
regulation of any governmental authority applicable to any of the ERI Parties or
any material agreement to which any of the ERI Parties is a party.

                  (b)      Shares. Schedule 2.3 sets forth the ownership of the
Shares held by the ERI Parties as of the date hereof.

         Section 2.4.      Representations and Warranties of the Belfer Group.
Each Belfer Person hereby severally and not jointly represents and warrants to
the other parties hereto as follows:

                  (a)      Authority. Such Belfer Person has all requisite
corporate or other power and authority to enter into this Agreement and to
consummate the transactions contemplated hereby. The execution and delivery by
such Belfer Person of this Agreement, and the consummation by such Belfer Person
of the transactions contemplated hereby, have been duly authorized by all
necessary corporate or other action on the part of such Belfer Person. This
Agreement has been duly executed and delivered by such Belfer Person and
constitutes a valid and binding obligation of such Belfer Person enforceable
against such Belfer Person in accordance with its terms. No consent, approval,
order or authorization of, or registration, declaration or filing (other than
the filing of an appropriate amendment to Schedule 13D in connection with the
transactions contemplated by this Agreement) with, any court, administrative
agency or commission or other governmental authority or instrumentality,
domestic or foreign, is

                                       5
<PAGE>

required by, or with respect to, such Belfer Person in connection with the
execution and delivery of this Agreement by such Belfer Person or the
consummation by such Belfer Person of the transactions contemplated hereby. The
execution and delivery of this Agreement by such Belfer Person and the
consummation by such Belfer Person of the transactions contemplated hereby by it
do not conflict with, or result in a breach of, any law or regulation of any
governmental authority applicable to such Belfer Person or any material
agreement to which such Belfer Person is a party.

         (b)      Shares. Schedule 2.4 sets forth the ownership of the Shares
held by each Belfer Person as of the date hereof.

                                  ARTICLE III
                               REGISTRATION RIGHTS

         Section 3.1.      Demand Registrations.

                  (a)      Requests for Registration. Each of the Medicor Group,
on behalf of the Medicor Parties, ERI, on behalf of the ERI Parties, and the
Belfer Group, on behalf of the Belfer Parties, shall have the right to request
registration under the Securities Act of all or part of their Registrable
Securities on Form S-1 or any similar long-form registration or, if available,
on Form S-2 or S-3 or any similar short-form registration ("Short-Form
Registrations") in accordance with this Article III. All registrations requested
pursuant to this Section 3.l(a) are referred to herein as "Demand
Registrations."

                  (b)      Short-Form Registrations. Demand Registrations will
be Short-Form Registrations whenever the Company is permitted to use any
applicable short form. The Company will use its best efforts to make Short-Form
Registrations available for the sale of Registrable Securities. Demand
Registration requests may be for shelf registrations if the Company is then
eligible to effect shelf registrations.

                  (c)      Restrictions on Demand Registrations. The
registration rights granted under this Section 3.1 are expressly subject to the
following terms and conditions:

                           1.       The Company will not be obligated to effect
any Demand Registration within six (6) months after the effective date of a
previous Demand Registration (including any registration or offering of shares
pursuant to the ERI letter to the Company dated September 11, 2003 (the "ERI
Letter") to the extent such registration or offering would constitute a "Demand
Registration" under and as defined in the Shareholders Agreement, provided that
solely for purposes of making such determination the registration requested in
the ERI Letter shall be deemed to have satisfied the requirements for an
effective "Demand Registration" set forth in Section 5.1(c)(3) of the
Shareholders Agreement).

                           2.       The Company may postpone for up to ninety
(90) days the filing or the effectiveness of a registration statement for a
Demand Registration (and any registration or underwritten offering of securities
pursuant to Section 3.1(c)(6), whether or not such registration or underwritten
offering constitutes a Demand Registration) if the Company notifies the

                                       6
<PAGE>

Shareholder Party initiating the Demand Registration (or such other registration
or underwritten offering pursuant to Section 3.1(c)(6)) within fifteen (15) days
after receipt of request for such registration (i) that the Company is at such
time conducting or about to conduct an underwritten public offering of its
securities for its own account and the Board of Directors has determined in its
good faith judgment that such offering would be materially adversely affected by
such registration or underwritten offering requested by such Shareholder Party
or (ii) that the Board of Directors has determined, in its good faith judgment,
that such Demand Registration (or registration or underwritten offering pursuant
to Section 3.1(c)(6)) would reasonably be expected to have an adverse effect on
any proposal or plan by the Company or any of its Subsidiaries to engage in any
acquisition of assets (other than in the ordinary course of business) or any
merger, consolidation, tender offer or similar transaction; provided, that, in
such event, the holders of Registrable Securities initially requesting such
Demand Registration (or, to the extent it would count as a Demand Registration,
such registration or underwritten offering pursuant to Section 3.1(c)(6)) will
be entitled to withdraw such request and, if such request is withdrawn, such
Demand Registration (or registration or underwritten offering pursuant to
Section 3.1(c)(6)) will not count as a Demand Registration hereunder and the
Company will pay all Registration Expenses in connection with such request.

                           3.       Any request for a Demand Registration shall
not be otherwise deemed to be effective unless such request includes the lesser
of (i) at least ten percent (10%) of the Company's outstanding Common Stock or
(ii) all of the Common Stock owned by the Shareholder Party or Shareholder
Parties making the request. Each request for a Demand Registration shall specify
the approximate number of Registrable Securities requested to be registered and
the anticipated per share price range for such offering.

                           4.       The Medicor Parties and the ERI Parties
shall each be entitled to initiate only three (3) Demand Registrations and the
Belfer Parties shall be entitled to initiate only two (2) Demand Registrations
to register Registrable Securities under the terms of this Section 3.1;
provided, if one of such Shareholder Parties joins in the Demand Registration
initiated by the other in accordance with Section 3.1(c)(5), the initiating
Shareholder Party shall not be deemed to have initiated the Demand Registration
for purposes (and solely for the purposes) of the limitation contained in this
sentence. Notwithstanding the foregoing, if the ERI Letter or the transactions
entered into as a consequence thereof constitute a "Demand Registration" under
and as defined in the Shareholders Agreement (provided that solely for purposes
of making such determination the registration requested in the ERI Letter shall
be deemed to have satisfied the requirements for an effective "Demand
Registration" set forth in Section 5.1(c)(3) of the Shareholders Agreement),
then the ERI Parties shall have the right to initiate only two (2) Demand
Registrations under the terms of this Section 3.1.

                           5.       If at any time or from time to time any of
the Shareholder Parties shall request registration of any Registrable Securities
in accordance with this Section 3.1, the Company shall give the other
Shareholder Parties prompt written notice of the proposed registration. The
other Shareholder Parties shall have the right to join in such registration by
giving notice to the Company within five (5) business days after such
Shareholder Party receives notice of the proposed registration from the Company
and the Company shall include in such registration the number of Registrable
Securities requested by such other Shareholder Parties on

                                       7
<PAGE>

the same terms and conditions as the Registrable Securities of the Shareholder
Party initiating the request. If the managing underwriter or underwriters of a
proposed offering for which securities of more than one of the Shareholder
Parties are included pursuant to this Section 3.1(c)(5) advise the Company in
writing that in its or their good faith judgment the total amount of securities
to be included in such offering exceeds the number which can be sold in such
offering within a price range reasonably acceptable to the Shareholder Parties,
then in such event the securities to be included in such offering shall be
allocated pro rata among such Shareholder Parties and their Permitted
Transferees participating in the offering based upon the number of Shares owned
by each such Shareholder Party and its Permitted Transferees.

                           6.       Any registration of Registrable Securities
requested to be made on a registration statement filed on Form S-3 pursuant to
Rule 415 of the Securities Act (each a "Shelf Registration Statement") shall
constitute a Demand Registration and be restricted for use pursuant to a firmly
underwritten offering of Common Stock. Each offering of Registrable Securities
pursuant to a Shelf Registration Statement (a "Shelf Offering") shall constitute
a Demand Registration (other than for purposes of Section 3.1(c)(1)) and must
satisfy all requirements for a Demand Registration set forth in this Article
III; provided, however, that a Shelf Offering for (i) sales of Common Stock
constituting block sales of less than five percent (5%) of the Common Stock
outstanding to institutional investors in solicited transactions, or (ii) sales
into the market in unsolicited brokers transactions will not be required to be a
firm commitment underwritten offering and will not constitute a Demand
Registration if the total amount of shares registered for sale in this manner
involves less than ten percent (10%) of the shares of Common Stock then
outstanding. Notwithstanding the foregoing, in the event that each of the
following occurs:

         (x) a Shareholder Party makes a Demand Registration to register shares
pursuant to a Shelf Registration Statement; and

         (y) the Shareholder Party requesting the Shelf Registration Statement
makes a Demand Registration in connection with a Shelf Offering (other than
pursuant to clauses (i) or (ii) of this Section 3.1(c)(6); and

         (z) no other Shareholder Party exercises its rights under Section
3.2(c)(5) hereof to participate in the registration described in clause (x) or
the Shelf Offering described in clause (y),

then the Shelf Offering described in clause (y) shall not count as a Demand
Registration for purposes of (and solely for purposes of) calculating the number
of Demand Registrations available to a Shareholder Party pursuant to Section
5.2(c)(3). The foregoing sentence shall apply only with respect to the first
Demand Registration for a Shelf Offering made by a Shareholder Party following a
Demand Registration made by such party requesting that shares be registered
pursuant to a Shelf Registration Statement, and shall not apply to any
subsequent Demand Registrations by such Shareholder Party made in connection
with Shelf Offerings.

                  (d)      Other Registration Rights. The Company will not grant
to any Person the right to request the Company to register any equity securities
of the Company with terms more

                                       8
<PAGE>

favorable to such Person than those granted in this Agreement without the prior
written consent of the Medicor Group, ERI and the Belfer Group.

                  (e)      Priority on Over-Allotments. In the event the
underwriters of any offering made pursuant to a Demand Registration exercise one
or more over-allotment options with respect such offering, the shares to be
included in such over-allotment option(s) will be allocated pro rata among the
holders of securities participating such offering on the basis of the number of
securities of each such party registered in the underlying registration to which
the over-allotment option relates.

         Section 3.2.      Piggyback Registrations.

                  (a)      Right to Piggyback. Whenever the Company proposes to
register any of its equity securities under the Securities Act (other than a
registration on Form S-4 or Form S-8 or any successor or similar forms and other
than a Demand Registration pursuant to Section 3.1) and the registration form to
be used may be used for the registration of Registrable Securities (a "Piggyback
Registration"), whether or not for sale for its own account, the Company will
give prompt written notice to the Medicor Group, on behalf of the Medicor
Parties, ERI, on behalf of the ERI Parties, and the Belfer Group, on behalf of
the Belfer Parties, of its intention to effect such a registration and will
include in such registration all Registrable Securities with respect to which
the Company has received written requests for inclusion therein within twenty
(20) days after the receipt of the Company's notice. The Company will use its
reasonable best efforts to include, and to cause the managing underwriters, if
applicable, to include in the proposed offering such Registrable Securities on
the same terms and conditions as the securities of the Company included in such
registration.

                  (b)      Priority on Primary Registrations. If a Piggyback
Registration is an underwritten primary registration on behalf of the Company,
and the managing underwriters advise the Company in writing that in their
opinion the number of securities requested to be included in such registration
exceeds the number which can be sold in such offering within a price range
reasonably acceptable to the Company, the Company will include in such
registration (i) first, the securities the Company proposes to sell, to the
extent of availability and, (ii) second, all other securities (including the
Registrable Securities) requested to be included in such registration, pro rata
among the respective holders thereof on the basis of the number of securities
owned by each such holder. In the event the underwriters of such primary
registration exercise one or more over-allotment options with respect thereto,
the shares to be included in such over-allotment option(s) will be allocated pro
rata among the Company and the holders of securities described in item (ii) of
this Section 3.2(b) on the basis of the number of securities of each such party
registered in underlying registration to which the over-allotment option
relates.

                  (c)      Priority on Secondary Registrations. If a Piggyback
Registration is an underwritten secondary registration on behalf of holders of
the Company's securities, and the managing underwriters advise the Company in
writing that in their opinion the number of securities requested to be included
in such registration exceeds the number which can be sold in such offering
within a price range reasonably acceptable to such holders, the securities which
can be included in such registration shall be allocated as follows: (i) first,
the securities requested to

                                       9
<PAGE>

be included in such registration by the holders of the Company's securities on
whose behalf the registration is being made, (ii) then, to the extent of
availability, securities to be registered for the account of the Company and
(iii) thereafter, to the extent of availability, to other security holders
exercising piggyback registration rights, pro rata based upon the number of
Shares owned by each such holder. In the event the underwriters of such
secondary registration exercise one or more over-allotment options with respect
thereto, the shares to be included in such over-allotment option(s) will be
allocated pro rata among the holders of the Company's securities on whose behalf
such secondary registration was made, the Company, and the holders of securities
described in item (iii) of this Section 3.2(c) on the basis of the number of
securities of each such party registered in the underlying registration to which
the over-allotment option relates.

                  (d)      Limited Purpose Shelf Registration Statement. In
order to facilitate the exercise by the Medicor Group, ERI and the Belfer Group
of their Piggyback Registration rights, upon request of either the Medicor
Group, ERI or the Belfer Group (any such request shall not constitute a Demand
Registration for purposes of Section 3.1), the Company shall prepare and file
with the Commission one or more registration statements on Form S-3 under Rule
415 of the Securities Act providing for the resale of Registrable Securities in
an amount of shares to be mutually agreed by Company and the Medicor Group, ERI
and the Belfer Group from time to time, provided, that such registration
statement on Form S-3 shall be restricted for use by the holders of the
securities subject to such registration statement only for participation
pursuant to Section 3.2 in a firmly underwritten public offering of Common Stock
proposed by the Company for the account of the Company or the account of any
other security holder.

         Section 3.3.      Holdback Agreements.

                  (a)      If requested in writing by the Company or the
managing underwriters, if any, of any registration effected pursuant to Sections
3.1 or 3.2, the Medicor Group agrees not to and will cause the other Medicor
Parties not to, ERI agrees not to and will cause the other ERI Parties not to,
and the Belfer Group agrees not to and will cause the other Belfer Parties not
to, effect any public sale or distribution (including sales pursuant to Rule
144) of equity securities of the Company, or any securities convertible into or
exchangeable or exercisable for such securities, during the time period
reasonably requested by the managing underwriters, not to exceed seven (7) days
prior to and the 90-day period beginning on the effective date of any
underwritten Demand Registration, any underwritten Piggyback Registration or
other underwritten registration by the Company of its securities (except as part
of such underwritten registration).

                  (b)      If requested in writing by the managing underwriters
of any registration effected pursuant to Section 3.1 or 3.2, the Company agrees
(i) not to effect any public sale or distribution of its equity securities, or
any securities convertible into or exchangeable or exercisable for such
securities, during the time period reasonably requested by the managing
underwriters, not to exceed seven days prior to and during the 90-day period
beginning on the effective date of any underwritten Demand Registration or any
underwritten Piggyback Registration (except as part of such underwritten
registration or pursuant to registrations on Form S-4 or Form S-8 or any
successor forms), and (ii) to cause each holder of its Common Stock, or any
securities convertible into or exchangeable or exercisable for Common Stock,
purchased

                                       10
<PAGE>

from the Company at any time after the date of this Agreement (other than in a
registered public offering), to so agree.

                  (c)      If the Company has previously filed a registration
statement with respect to Registrable Securities pursuant to Sections 3.1 or 3.2
hereof or pursuant to Sections 5.1 or 5.2 of the Shareholders Agreement, and if
such previous registration has not been withdrawn or abandoned, the Company will
not file or cause to be effected any other registration of any of its equity
securities or securities convertible or exchangeable into or exercisable for its
equity securities under the Securities Act (except on Form S-4 or Form S-8 or
any successor forms), whether on its own behalf or at the request of any holder
or holders of such securities, until a period of at least ninety (90) days has
elapsed from the effective date of such previous registration.

         Section 3.4.      Registration Procedures. Whenever the Medicor Group,
on behalf of the Medicor Parties, ERI, on behalf of the ERI Parties, or the
Belfer Group on behalf of the Belfer Parties has requested that any Registrable
Securities be registered pursuant to this Agreement, the Company will use its
best efforts to effect the registration and the sale of such Registrable
Securities in accordance with the intended method of disposition thereof, and
pursuant thereto the Company will as expeditiously as possible:

                  (a)      prepare and file with the Commission a registration
statement with respect to such Registrable Securities and thereafter use its
reasonable best efforts to cause such registration statement to become effective
(provided that, before filing a registration statement or prospectus or any
amendments or supplements thereto, the Company will furnish to the counsel
selected by the holders of the Registrable Securities covered by such
registration statement copies of all such documents proposed to be filed, which
documents will be subject to reasonable review of such counsel);

                  (b)      prepare and file with the Commission such amendments
and supplements to such registration statement and the prospectus used in
connection therewith as may be necessary to keep such registration statement
effective for a period of either (i) not less than six months (subject to
extension pursuant to Section 3.7(b)) or, if such registration statement relates
to an underwritten offering, such longer period as in the opinion of counsel for
the underwriters a prospectus is required by law to be delivered in connection
with sales of Registrable Securities by an underwriter or dealer or (ii) such
shorter period as will terminate when all of the securities covered by such
registration statement have been disposed of in accordance with the intended
methods of disposition by the seller or sellers thereof set forth in such
registration statement (but in any event not before the expiration of any longer
period required under the Securities Act), and to comply with the provisions of
the Securities Act with respect to the disposition of all securities covered by
such registration statement until such time as all of such securities have been
disposed of in accordance with the intended methods of disposition by the seller
or sellers thereof set forth in such registration statement;

                  (c)      furnish to each seller of Registrable Securities such
number of copies of such registration statement, each amendment and supplement
thereto, the prospectus included in such registration statement (including each
preliminary prospectus) and such other documents as

                                       11
<PAGE>

such seller may reasonably request in order to facilitate the disposition of the
Registrable Securities owned by such seller;

                  (d)      use its best efforts to register or qualify such
Registrable Securities under such other securities or blue sky laws of such
jurisdictions as any seller reasonably requests and do any and all other acts
and things which may be reasonably necessary or advisable to enable such seller
to consummate the disposition in such jurisdictions of the Registrable
Securities owned by such seller (provided that the Company will not be required
to (i) qualify generally to do business in any jurisdiction where it would not
otherwise be required to qualify but for this subparagraph, (ii) subject itself
to taxation in any such jurisdiction or (iii) consent to general service of
process in any such jurisdiction);

                  (e)      notify each seller of such Registrable Securities, at
any time when a prospectus relating thereto is required to be delivered under
the Securities Act, upon discovery that, or upon the discovery of the happening
of any event as a result of which, the prospectus included in such registration
statement contains an untrue statement of a material fact or omits any fact
necessary to make the statements therein not misleading in the light of the
circumstances under which they were made, and, at the request of any such
seller, the Company will prepare and furnish to such seller a reasonable number
of copies of a supplement or amendment to such prospectus so that, as thereafter
delivered to the purchasers of such Registrable Securities, such prospectus will
not contain an untrue statement of a material fact or omit to state any fact
necessary to make the statements therein not misleading in the light of the
circumstances under which they were made;

                  (f)      cause all such Registrable Securities to be listed on
each securities exchange on which similar securities issued by the Company are
then listed and, if not so listed, to be listed on the Nasdaq National Market or
the New York Stock Exchange;

                  (g)      provide a transfer agent and registrar for all such
Registrable Securities not later than the effective date of such registration
statement;

                  (h)      enter into such customary agreements (including
underwriting agreements in customary form for similar offerings) and take all
such other actions as the holders of a majority of the Registrable Securities
being sold or the underwriters, if any, reasonably request in order to expedite
or facilitate the disposition of such Registrable Securities (including, without
limitation, effecting a stock split or a combination of shares);

                  (i)      make available for inspection by any seller of
Registrable Securities, any underwriter participating in any disposition
pursuant to such registration statement, and any attorney, accountant or other
agent retained by any such seller or underwriter, all financial and other
records, pertinent corporate documents and properties of the Company, and cause
the Company's officers, Directors, employees and independent accountants to
supply all information reasonably requested by any such seller, underwriter,
attorney, accountant or agent in connection with such registration statement;

                                       12
<PAGE>

                  (j)      otherwise use its reasonable best efforts to comply
with all applicable rules and regulations of the Commission, and make available
to its security holders, as soon as reasonably practicable, an earnings
statement covering the period of at least twelve months beginning with the first
day of the Company's first full calendar quarter after the effective date of the
registration statement, which earnings statement shall satisfy the provisions of
Section 11(a) of the Securities Act and Rule 158 thereunder;

                  (k)      in the event of the issuance of any stop order,
injunction or other order or requirement suspending the effectiveness of a
registration statement, or of any order suspending or preventing the use of any
related prospectus or suspending the qualification of any securities included in
such registration statement for sale in any jurisdiction, the Company will use
its reasonable best efforts promptly to obtain the withdrawal of such order and
to notify the holders of all of the Registrable Securities covered by the
registration statement of such order;

                  (l)      obtain a cold comfort letter, dated the effective
date of such registration statement (and, if such registration includes an
underwritten public offering, dated the date of the closing under the
underwriting agreement), signed by the Company's independent public accountants
in customary form and covering such matters of the type customarily covered by
cold comfort letters as the holders of a majority of the Registrable Securities
being sold reasonably request (provided that such Registrable Securities
constitute at least 10% of the securities covered by such registration
statement);

                  (m)      provide a legal opinion of the Company's outside
counsel, dated the effective date of such registration statement (and, if such
registration includes an underwritten public offering, dated the date of the
closing under the underwriting agreement), with respect to the registration
statement, each amendment and supplement thereto, the prospectus included herein
(including the preliminary prospectus) and such other documents relating thereto
in customary form and covering such matters of the type customarily covered by
legal opinions of such nature;

                  (n)      promptly furnish to the managing underwriter, if any,
and each seller of Registrable Securities copies of any written request by the
Commission or any state securities authority for amendments or supplements to a
registration statement or prospectus or for additional information; and

                  (o)      make reasonably available its employees and personnel
and otherwise provide reasonable assistance to any underwriters in the marketing
of Registrable Securities in any underwritten offering.

         The Company may require each seller of Registrable Securities as to
which any registration is being effected to furnish the Company such information
regarding such seller and the distribution of such securities as the Company may
from time to time reasonably request in writing.

                                       13
<PAGE>

         Section 3.5.      Registration Expenses.

                  (a)      The Company shall pay all Registration Expenses
relating to any registration of Registrable Securities hereunder. "Registration
Expenses" shall mean any and all fees and expenses incident to the Company's
performance of or compliance with this Article III, including, without
limitation: (i) Commission, stock exchange or National Association of Securities
Dealers, Inc. registration and filing fees and all listing fees and fees with
respect to the inclusion of securities on the Nasdaq National Market, (ii) fees
and expenses of compliance with state securities or "blue sky" laws and in
connection with the preparation of a "blue sky" survey, including, without
limitation, reasonable fees and expenses of blue sky counsel, (iii) printing
expenses, (iv) messenger and delivery expenses, (v) fees and disbursements of
counsel for the Company, (vi) with respect to each registration, reasonable fees
and disbursements of one counsel for the selling holders of Shares (selected by
the holders making the Demand Registration request, in the case of a
registration pursuant to Section 3.1, and selected by the holders of a majority
of the Registrable Securities included in such registration, in the case of a
registration pursuant to Section 3.2) as well as of one local counsel, (vii)
fees and disbursements of all independent public accountants (including the
expenses of any audit and/or "cold comfort" letter) and fees and expenses of
other persons, including special experts, retained by the Company, and (viii)
any other fees and disbursements of underwriters, if any, customarily paid by
issuers or sellers of securities.

                  (b)      Notwithstanding the foregoing, (i) the provisions of
this Section 3.5 shall be deemed amended to the extent necessary to cause these
expense provisions to comply with "blue sky" laws of each state in which the
offering is made and (ii) in connection with any registration hereunder, each
holder of Registrable Securities being registered shall pay all underwriting
discounts and commissions and transfer taxes, if any, attributable to the
Registrable Securities included in the offering by such holder.

         Section 3.6.      Indemnification.

                  (a)      The Company agrees to indemnify and hold harmless, to
the extent permitted by law, each holder of Registrable Securities, its officers
and Directors and each Person who controls such holder (within the meaning of
the Securities Act) against any losses, claims, damages, liabilities, joint or
several, to which such holder or any such Director or officer or controlling
person may become subject under the Securities Act or otherwise, insofar as such
losses, claims, damages or liabilities (or actions or proceedings, whether
commenced or threatened, in respect thereof) arise out of or are based upon (i)
any untrue or alleged untrue statement of a material fact contained (A) in any
registration statement, prospectus or preliminary prospectus or any amendment
thereof or supplement thereto or (B) in any application or other document or
communication (in this Section 3.6 collectively called an "application")
executed by or on behalf of the Company or based upon written information
furnished by or on behalf of the Company filed in any jurisdiction in order to
qualify any securities covered by such registration statement under the "blue
sky" or securities laws thereof, or (ii) any omission or alleged omission of a
material fact required to be stated therein or necessary to make the statements
therein not misleading, and the Company will reimburse such holder and each such
Director, officer and controlling person for any legal or any other expenses
incurred by them in connection with

                                       14
<PAGE>

investigating or defending any such loss, claim, liability, action or
proceeding; provided that the Company shall not be liable in any such case to
the extent that any such loss, claim, damage, liability (or action or proceeding
in respect thereof) or expense arises out of or is based upon an untrue
statement or alleged untrue statement, or omission or alleged omission, made in
such registration statement, any such prospectus or preliminary prospectus or
any amendment or supplement thereto, or in any application, in reliance upon and
in conformity with written information prepared and furnished to the Company by
such holder expressly for use therein or by such holder's failure to deliver a
copy of the registration statement or prospectus or any amendments or
supplements thereto after the Company has furnished such holder with a
sufficient number of copies of the same. In connection with an underwritten
offering, the Company will indemnify such underwriters, their officers and
Directors and each Person who controls such underwriters (within the meaning of
the Securities Act) to the same extent as provided above with respect to the
indemnification of the holders of Registrable Securities.

                  (b)      In connection with any registration statement in
which a holder of Registrable Securities is participating, each such holder will
furnish to the Company in writing such information and documents as the Company
reasonably requests for use in connection with any such registration statement
or prospectus and, to the extent permitted by law, will indemnify and hold
harmless the Company, its Directors and officers and each other Person who
controls the Company (within the meaning of the Securities Act) against any
losses, claims, damages, liabilities, joint or several, to which the Company or
any such Director or officer or controlling person may become subject under the
Securities Act or otherwise, insofar as such losses, claims, damages or
liabilities (or actions or proceedings, whether commenced or threatened, in
respect thereof) arise out of or are based upon (i) any untrue or alleged untrue
statement of a material fact contained in the registration statement, prospectus
or preliminary prospectus or any amendment thereof or supplement thereto or in
any application or (ii) any omission or alleged omission of a material fact
required to be stated therein or necessary to make the statements therein not
misleading, but only to the extent that such untrue statement or omission is
made in such registration statement, any such prospectus or preliminary
prospectus or any amendment or supplement thereto, or in any application, in
reliance upon and in conformity with written information prepared and furnished
to the Company by such holder expressly for use therein, and such holder will
reimburse the Company and each such Director, officer and controlling person for
any legal or any other expenses incurred by them in connection with
investigating or defending any such loss, claim, liability, action or
proceeding; provided that the obligation to indemnify will be individual to each
holder and will be limited to the net amount of proceeds received by such holder
from the sale of Registrable Securities pursuant to such registration statement.

                  (c)      Any Person entitled to indemnification hereunder will
(i) give prompt written notice to the indemnifying party of any claim with
respect to which it seeks indemnification and (ii) unless in such indemnified
party's reasonable judgment a conflict of interest between such indemnified and
indemnifying parties may exist with respect to such claim, permit such
indemnifying party to assume the defense of such claim with counsel reasonably
satisfactory to the indemnified party. If such defense is assumed, the
indemnifying party will not be subject to any liability for any settlement made
by the indemnified party without its consent (but such consent will not be
unreasonably withheld). An indemnifying party who is not entitled

                                       15
<PAGE>

to, or elects not to, assume the defense of a claim will not be obligated to pay
the fees and expenses of more than one counsel for all parties indemnified by
such indemnifying party with respect to such claim, unless in the reasonable
judgment of any indemnified party a conflict of interest may exist between such
indemnified party and any other of such indemnified parties with respect to such
claim.

                  (d)      The indemnification provided for under this Agreement
will remain in full force and effect regardless of any investigation made by or
on behalf of the indemnified party or any officer, Director or controlling
Person of such indemnified party and will survive the transfer of securities by
any holder thereof. The Company also agrees to make such provisions, as are
reasonably requested by any indemnified party, for contribution to such party in
the event the Company's indemnification is unavailable for any reason.

         Section 3.7.      Participation in Underwritten Registrations.

                  (a)      If requested by the underwriters for any underwritten
offering pursuant to a Demand Registration requested under Section 3.1, the
Company shall enter into a customary underwriting agreement with the
underwriters. Such underwriting agreement shall be satisfactory in form and
substance to the Person who requested such registration and shall contain such
representations and warranties by, and such other agreements on the part of, the
Company and such other terms as are generally prevailing in agreements of that
type, including, without limitation, indemnities and contribution agreements.
Such underwriting agreement shall also contain such representations, warranties,
indemnities and contributions by the participating holders as are customary in
agreements of that type. In the case of a registration pursuant to Section 3.2
hereof, if the Company shall have determined to enter into any underwriting
agreements in connection therewith, all of the holders' Registrable Securities
to be included in such registration shall be subject to such underwriting
agreement. Such underwriting agreement shall also contain such representations,
warranties, indemnities and contributions by the participating holders as are
customary in agreements of that type.

                  (b)      Each Person that is participating in any registration
hereunder agrees that, upon receipt of any notice from the Company of the
happening of any event of the kind described in Section 3.4(e) above, such
Person will forthwith discontinue the disposition of its Registrable Securities
pursuant to the registration statement until such Person's receipt of the copies
of a supplemented or amended prospectus as contemplated by such Section 3.4(e).
In the event the Company shall give any such notice, the applicable time period
mentioned in Section 3.4(b) during which a registration statement is to remain
effective shall be extended by the number of days during the period from and
including the date of the giving of such notice pursuant to this paragraph to
and including the date when each seller of a Registrable Security covered by
such registration statement shall have received the copies of the supplemented
or amended prospectus contemplated by Section 3.4(e).

         Section 3.8.      Current Public Information. At all times after the
Company has filed a registration statement with the Commission pursuant to the
requirements of either the Securities Act or the Exchange Act, the Company will
file all reports required to be filed by it under the Act and the Exchange Act
and the rules and regulations adopted by the Commission thereunder, and

                                       16
<PAGE>

will take such further action as any holder or holders of Registrable Securities
may reasonably request, all to the extent required to enable such holders to
sell Registrable Securities pursuant to Rule 144.

         Section 3.9.      Cooperation. If the Company determines to authorize
and/or issue any capital stock or other debt or equity securities in a public
offering, each of the Shareholder Parties and their Permitted Transferees agrees
to cooperate with the Company and to take all action necessary to assist the
Company in consummating such transaction.

                                   ARTICLE IV
                               GENERAL PROVISIONS

         Section 4.1.      Notices. Any notice required to be given hereunder
shall be sufficient if in writing, and sent by facsimile transmission and by
courier service (with proof of service), hand delivery or certified or
registered mail (return receipt requested and first-class postage prepaid),
addressed as follows:

                  If to the Belfer Group:

                           Robert A. Belfer
                           767 Fifth Avenue, 46th Floor
                           New York, New York 10153
                           Fax Number: (212) 644-2396
                           Phone Number: (212) 644-2200

                  With a copy to:

                           Laurence D. Belfer
                           767 Fifth Avenue, 46th Floor
                           New York, New York 10153
                           Fax Number: (212) 644-2396
                           Phone Number: (212) 644-0561

                  If to Westport:

                           Donald D. Wolf,
                           Chairman and Chief Executive Officer
                           1670 Broadway, Suite 2800
                           Denver, CO. 80202
                           Fax Number: (303) 573-5609
                           Phone Number: (303) 573-5404

                                       17
<PAGE>

                  With a copy to:

                           Akin Gump Strauss Hauer & Feld LLP
                           1700 Pacific Avenue, Suite 4100
                           Dallas, Texas 75201-4675
                           Attention: Michael E. Dillard, P.C.
                           Fax Number: (214) 969-4343
                           Phone Number: (214) 969-2800

                  If to the Medicor Group:

                           Medicor Foundation
                           Landstrasse 11
                           Postfach 130
                           FL-9495 Triesen
                           Liechtenstein
                           Attention: Anton M. Lotzer
                           Fax (423) 233 3934
                           Tel (423) 239 6050

                  And to:

                           Westport Energy LLC
                           c/o Westport Investments Limited
                           Lyford Manor
                           Lyford Cay
                           P.O. Box N-7776
                           Nassau, Bahamas
                           Fax Number: (242) 362-5788

                  With a copy to:

                           Kenneth S. Witt
                           Greenberg Traurig, LLP
                           1200 17th Street, Suite 2400
                           Denver, CO 80202
                           Telephone: (303) 572-6510
                           Telecopy: (303) 572-6540

                                       18
<PAGE>

                  And to:

                           Michael Russell
                           Dr. Richard J. Haas Partners
                           Dukes Court
                           32 Duke Street, St. James's
                           London, SW1Y 6DF
                           Fax Number: 020.7.321.5242
                           Phone Number: 020.7.321.5200

                  If to ERI Investments, Inc.:

                           ERI Investments, Inc.
                           801 West Street, 2nd Floor
                           Wilmington, DE 19801-1545
                           Attention: Treasurer
                           Telephone: (302) 656-5590
                           Telecopy: (302) 428-1410

                  With a copy to:

                           Johanna G. O'Loughlin
                           Vice President, General Counsel and Secretary
                           Equitable Resources, Inc.
                           One Oxford Centre, Suite 3300
                           Pittsburgh, PA 15219
                           Telephone: (412) 553-7760
                           Telecopy: (412) 553-5970

                  And to:

                           Stephen W. Johnson, Esquire
                           Reed Smith LLP
                           435 Sixth Avenue
                           Pittsburgh, PA 15219-1886
                           Telephone: (412) 288-3131
                           Telecopy: (412) 288-3063

or to such other address as any Shareholder Party shall specify by written
notice so given, and such notice shall be deemed to have been delivered as of
the date so telecommunicated, personally delivered or mailed.

         Section 4.2.      Assignment; Binding Effect; Benefit. Any Shareholder
Party that Transfers to a Permitted Transferee shall promptly give written
notice of such Transfer to the other Shareholder Parties and the Company
pursuant to Section 4.1 and shall deliver to such Shareholder Parties and the
Company a copy of the written agreement pursuant to which the

                                       19
<PAGE>

Permitted Transferee has agreed to be bound by the terms of this Agreement.
Other than Transfers to Permitted Transferees, neither this Agreement nor any of
the rights, interests or obligations hereunder shall be assigned by any of the
Shareholder Parties or their Permitted Transferees without the prior written
consent of the other Shareholder Parties; provided, that the Medicor Parties,
the ERI Parties and the Belfer Parties may assign all or a portion of their
rights under Article III in connection with any Transfer of Registrable
Securities made in accordance with this Agreement if immediately after the
Transfer, the transferee beneficially owns at least ten percent (10%) of the
Common Stock of the Company then outstanding, in which event each transferee
will have rights and obligations under Article III as if it was a party to this
Agreement to the extent of such assignment. Subject to the preceding sentence,
this Agreement shall be binding upon and shall inure to the benefit of the
parties hereto and their respective successors and assigns. Notwithstanding
anything contained in this Agreement to the contrary, nothing in this Agreement,
express or implied, is intended to confer on any person other than the parties
hereto or their respective heirs, successors, executors, administrators and
assigns any rights, remedies, obligations or liabilities under or by reason of
this Agreement.

         Section 4.3       Entire Agreement. This Agreement, the exhibits and
schedules hereto and any certificate delivered by the parties hereto in
connection herewith constitute the entire agreement among the parties hereto
with respect to the subject matter hereof and supersede all prior agreements and
understandings (oral and written) among the parties with respect hereto.

         Section 4.4       Amendment. No amendment, modification or waiver of
this Agreement shall be effective against any party hereto unless it shall be in
writing and signed by such party. Notwithstanding the foregoing, Exhibit A shall
be amended or modified from time to time to reflect Transfers to Permitted
Transferees by giving written notice of such Transfers to the Shareholder
Parties and the Company pursuant to Section 4.1.

         Section 4.5       Governing Law; Jurisdiction. This Agreement shall be
governed by and construed in accordance with the laws of the State of Nevada
without regard to its rules of conflict of laws. The Shareholder Parties and the
Company agree that any suit, action or proceeding arising out of, or with
respect to, this Agreement or any judgment entered by any court in respect
thereof may be brought only in the courts of the State of Nevada or the federal
district courts located within the State of Nevada and the Shareholder Parties
and the Company hereby accept the exclusive jurisdiction of those courts for the
purpose of any suit, action or proceeding.

         Section 4.6       Counterparts. This Agreement may be executed by the
parties hereto in separate counterparts, each of which when so executed and
delivered shall be an original, but all such counterparts shall together
constitute one and the same instrument. Each counterpart may consist of a number
of copies of this Agreement, each of which may be signed by less than all of the
parties hereto, but together all such copies are signed by all of the parties
hereto.

         Section 4.7       Headings. Headings of the Articles and Sections of
this Agreement are for convenience only and shall be given no substantive or
interpretive effect whatsoever.

                                       20

<PAGE>

         Section 4.8       Interpretation. In this Agreement, unless the context
otherwise requires: (i) words describing the singular number shall include the
plural and vice versa; (ii) "including" shall mean including, without
limitation; (iii) words denoting any gender shall include all genders; and (iv)
words denoting natural persons shall include corporations and partnerships and
vice versa.

         Section 4.9       Incorporation of Exhibits and Schedules. All exhibits
and schedules hereto are hereby incorporated herein and made a part hereof for
all purposes as if fully set forth herein.

         Section 4.10      Severability. Any term or provision of this Agreement
which is invalid or unenforceable in any jurisdiction shall, as to that
jurisdiction, be ineffective to the extent of such invalidity or
unenforceability without rendering invalid or unenforceable the remaining terms
and provisions of this Agreement or otherwise affecting the validity or
enforceability of any of the terms or provisions of this Agreement in any other
jurisdiction. If any provision of this Agreement is so broad as to be
unenforceable, the provision shall be interpreted to be only so broad as is
enforceable.

         Section 4.11      Enforcement of Agreement. The parties hereto agree
that irreparable damage would occur in the event that any of the provisions of
this Agreement were not performed in accordance with its specific terms or was
otherwise breached. It is accordingly agreed that the Company, the Shareholder
Parties and their Permitted Transferees shall be entitled to an injunction or
injunctions to prevent breaches of this Agreement and to enforce specifically
the terms and provisions hereof in any court, this being in addition to any
other remedy to which they may be entitled at law or in equity.

         Section 4.12      Confidentiality. None of the Medicor Parties, their
Affiliates, employees, agents or representatives, the ERI Parties, their
Affiliates, employees, agents or representatives nor the Belfer Parties, their
Affiliates, employees, agents or representatives shall disclose to any third
party any information obtained about the Company or its operations or business
which it may have acquired pursuant to this Agreement or the Shareholders
Agreement without the prior written consent of the Company; provided, that any
information that is otherwise publicly available, without breach of this
provision, or has been obtained from a third party without a breach of such
third party's duties, shall not be deemed confidential information.

         Section 4.13      Effectiveness; Termination. This Agreement shall be
effective as of the date of termination of the Shareholders Agreement pursuant
to the terms of that certain Termination Agreement dated as of October 1, 2003,
by and among the Company and Shareholder Parties (the "Effective Date") and
shall continue in effect with respect to a Shareholder Party and its Permitted
Transferees as long as it holds Registrable Securities, provided, however, that
this Agreement may be terminated at any time when all of the parties who are
then bound hereby mutually consent to terminate this Agreement in writing.
Notwithstanding anything to the contrary contained in this Section 4.13, the
provisions of Section 4.12 shall not terminate.

                                       21

<PAGE>

         Section 4.14      Belfer Group Representative. Robert A. Belfer shall
be the initial Belfer Group representative (the "Belfer Group Representative").
The Belfer Group Representative may be changed by delivery of a written
notification delivered to the parties hereto and executed by all of the members
of the Belfer Group. Each member of the Belfer Group hereby appoints the person
or entity who is, from time to time, duly appointed under this Section 4.14 as
the Belfer Group Representative to give any consent or approval, exercise any
right or take any action contemplated under this Agreement on behalf of the
Belfer Group. The members of the Belfer Group shall be so bound by the Belfer
Group Representative and the parties to this Agreement shall be entitled to rely
on the actions taken by the Belfer Group Representative contemplated by this
Agreement.

         Section 4.15      Medicor Group Representative. Michael Russell shall
be the initial Medicor Group representative (the "Medicor Group
Representative"). The Medicor Group Representative may be changed by delivery of
a written notification delivered to the parties hereto and executed by all of
the members of the Medicor Group. Each member of the Medicor Group hereby
appoints the person or entity who is, from time to time, duly appointed under
this Section 4.15 as the Medicor Group Representative to give any consent or
approval, exercise any right or take any action contemplated under this
Agreement on behalf of the Medicor Group. The members of the Medicor Group shall
be so bound by the Medicor Group Representative and the parties to this
Agreement shall be entitled to rely on the actions taken by the Medicor Group
Representative contemplated by this Agreement. The inclusion of WELLC and
Medicor in a group, referenced in this Agreement as the Medicor Group, and the
appointment by WELLC and Medicor of a Medicor Group Representative, as set forth
in this Section 4.15, are merely for administrative convenience. Each of Medicor
and WELLC is a distinct legal entity, and neither Medicor nor WELLC controls the
other or is under the common control of a third party.

                                       22

<PAGE>

         IN WITNESS WHEREOF, the parties have executed this Registration Rights
Agreement and caused the same to be duly delivered on their behalf as of the day
and year first written above, to be effective as of the Effective Date.

                                 WESTPORT RESOURCES CORPORATION

                                 By:    /s/ DONALD D. WOLF
                                 Name:  Donald D. Wolf
                                 Title: Chief Executive Officer

                                 WESTPORT ENERGY LLC

                                   By: WESTPORT INVESTMENTS LIMITED, its
                                   Managing Member

                                     By:    /s/ MICHAEL RUSSELL
                                     Name:  Michael Russell
                                     Title: Duly Authorized Signatory

                                 ERI INVESTMENTS, INC.

                                 By:    /s/ KENNETH J. KUBACKI
                                 Name:  Kenneth J. Kubacki
                                 Title: Vice President

                                 MEDICOR FOUNDATION

                                 By:    /s/ ANTON M. LOTZER
                                 Name:  Anton M. Lotzer
                                 Title: Member of the Foundation Board

                                 By:    /s/ ALBIN A. JOHANN
                                 Name:  Albin A. Johann
                                 Title: Member of the Foundation Board/Secretary

                                 /s/ ROBERT A. BELFER
                                 Robert A. Belfer, individually

                                      S-1

<PAGE>

                                 THE ROBERT A. AND RENEE E. BELFER
                                 FAMILY FOUNDATION

                                 By:    /s/ ROBERT A. BELFER
                                 Name:  Robert A. Belfer
                                 Title: Trustee and Donor

                                 BELFER CORP.

                                 By:    /s/ ROBERT A. BELFER
                                 Name:  Robert A. Belfer
                                 Title: President

                                 RENEE HOLDINGS PARTNERSHIP, L.P.

                                 By:    /s/ Robert A. Belfer
                                 Name:  Robert A. Belfer
                                 Title: General Partner

                                 LDB CORP.

                                 By:    /s/ LAURENCE D. BELFER
                                 Name:  Laurence D. Belfer
                                 Title: President

                                      S-2

<PAGE>

                                 ROBERT A. BELFER 1990 FAMILY TRUST

                                 By:    /s/ LAURENCE D. BELFER
                                 Name:  Laurence D. Belfer
                                 Title: Trustee

                                 VANTZ LIMITED PARTNERSHIP

                                 By: VANTZ LLC,
                                        Its General Partner

                                        By:    /s/ LAURENCE D. BELFER
                                        Name:  Laurence D. Belfer
                                        Title: Managing Member

                                 LDB TWO CORP.

                                 By:    /s/ Laurence D. Belfer
                                 Name:  Laurence D. Belfer
                                 Title: President

                                 BELFER TWO CORP.

                                 By:    /s/ ROBERT A. BELFER
                                 Name:  Robert A. Belfer
                                 Title: President

                                 LIZ PARTNERS, L.P.

                                 By: Liz Associates LLC,
                                        Its General Partner

                                        By:    /s/ ROBERT A. BELFER
                                        Name:  Robert A. Belfer
                                        Title: Managing Member

                                      S-3

<PAGE>

                                    EXHIBIT A

                              CERTAIN STOCKHOLDERS

The Robert A. and Renee E. Belfer Family Foundation
Robert A. Belfer
Belfer Corp.
Renee Holdings Partnership, L.P.
LDB Corp.
Robert A. Belfer 1990 Family Trust
Vantz Limited Partnership
LDB Two Corp.
Belfer Two Corp.
Liz Partners, L.P.

<PAGE>

                                  SCHEDULE 2.2

                         OWNERSHIP - EACH MEDICOR PERSON

<TABLE>
<CAPTION>
                                                                            Ownership of Common
                                                                                  Stock
                Stockholder                                                 as of the date hereof
-------------------------------------------------------------------------------------------------
<S>                                                                         <C>
               Medicor Foundation                                              11,000,000
              Westport Energy LLC                                               3,238,001
                                                                               ==========
                                                             Total             14,238,001
Percentage of total outstanding Common Stock as of the date hereof                  21.17%
</TABLE>

<PAGE>

                                  SCHEDULE 2.3

                            OWNERSHIP -- ERI PARTIES

<TABLE>
<CAPTION>
                                                                         Ownership of Common
                                                                                Stock
                 Stockholder                                            as of the date hereof
---------------------------------------------------------------------------------------------
<S>                                                                     <C>
             ERI Investments, Inc.                                           13,006,152
                                                                             ==========
                                                             Total           13,006,152
Percentage of total outstanding Common Stock as of the date hereof                19.34%
</TABLE>

<PAGE>

                                  SCHEDULE 2.4

                         OWNERSHIP - EACH BELFER PERSON

<TABLE>
<CAPTION>
                                                                                               Ownership of Common
                                                                                               Stock as of the date
                               Stockholder                                                           hereof
-------------------------------------------------------------------------------------------------------------------
<S>                                                                                            <C>
The Robert A. and Renee E. Belfer Family Foundation(1)                                              174,793
Robert A. Belfer                                                                                         --
Belfer Corp.(1)                                                                                   1,003,270
Renee Holdings Partnership, L.P.(1)                                                                 492,283
LDB Corp.(2)                                                                                        112,552
Robert A. Belfer 1990 Family Trust(2)                                                               230,040
Vantz Limited Partnership (2)                                                                       261,610
LDB Two Corp.(2)                                                                                    823,031
Belfer Two Corp.(1)                                                                               1,157,309
Liz Partners, L.P.(1)                                                                               495,899
                                                                                                 ==========
                                                                      Total                       4,750,787
         Percentage of total outstanding Common Stock as of the date hereof                            7.06%
</TABLE>

-----------

(1)      c/o Robert A. Belfer, 767 Fifth Avenue, 46th Floor, New York, New York
         10153

(2)      c/o Laurence D. Belfer, 767 Fifth Avenue, 46th Floor, New York, New
         York 10153