<PAGE>   1
                                                                    EXHIBIT 10.1

March 29, 2001


Mr. David H. Hayden
Executive Chairman and Founder
Critical Path
320 First Street
San Francisco, CA 94105

Re: Finder and Advisory Agreement

Dear David:

This letter agreement sets forth the terms pursuant to which Critical Path, Inc.
(the "Company") has agreed to engage Vectis Group, LLC and its subsidiaries and
affiliates (collectively referred to herein as "Vectis Group") to act as a
finder and advisor in connection with the private placement by the Company to
Qualified Institutional Buyers (as defined in Rule 144A of Regulation D
promulgated by the Securities and Exchange Commission) of up to $100 million of
any capital stock (common, preferred, preference or otherwise) or other equity
or ownership interest in the Company and any securities, warrants, options or
other rights to acquire any such capital stock or other equity or ownership
interest (the "Securities").

1.      Appointment and Acceptance. The Company hereby appoints Vectis Group as
a non-exclusive finder and advisor in connection with the proposed private
placement of the Securities with one or more Qualified Prospective Purchasers
(as defined below). Vectis Group hereby accepts such appointment, subject to the
terms and conditions of this letter agreement. Vectis Group agrees that in its
capacity hereunder it will use its commercially reasonable efforts to arrange
introductions and provide such other advisory services and activities as may be
agreed upon by Vectis Group and the Executive Chairman of the Company from time
to time in connection with the private placement of the Securities. Such
services include, without limitation, contacting potential purchasers of the
Company's securities and assisting in the preparation of the Information (as
defined below) and participating in discussions with potential purchasers of the
Company's securities. For purposes of this Agreement, a "Qualified Prospective
Purchaser" shall mean entities who are Qualified Institutional Buyers who Vectis
Group and the Executive Chairman of the Company from time to time agree in
writing are to be deemed Qualified Prospective Purchasers for purposes of this
letter agreement.

2.      Fees and Expenses.

        (a) As compensation to Vectis Group for its services hereunder, the
Company hereby agrees to pay Vectis Group as follows: promptly upon a closing
(each, a "Closing") of a sale of the Securities to Vectis Group or any Qualified
Prospective Purchaser, the Company hereby agrees to pay to Vectis Group a fee
(each, a "Finder's Fee") in an amount equal to five percent


<PAGE>   2
Mr. David H. Hayden
March 29, 2001
Page 2

(5%) of the gross proceeds raised by the Company pursuant to each such sale.
Each Finder's Fee shall, at the option of Vectis Group, be payable in (i) cash;
(ii) shares of the Securities (of the type issued by the Company at such
Closing) in an amount equal to (A) the Finder's Fee divided by (B) the gross
proceeds raised divided by the number of Securities issued to Qualified
Prospective Purchasers; or (iii) a combination of cash and shares of the
Securities.

        (b) Promptly upon the request of Vectis Group, the Company will
reimburse Vectis Group for its reasonable out-of-pocket expenses incurred during
the term of this engagement with respect to or arising from the services
rendered by Vectis Group hereunder, including, without limitation, the
professional fees and disbursements of its advisors, including its legal counsel
(it being understood that the retention of any advisor (other than legal
counsel) by Vectis Group shall only be made with the prior approval of the
Company).

        (c) All fees and expenses payable hereunder shall be paid net of all
applicable withholding and similar taxes.

3.      Information.

        (a) The Company will furnish Vectis Group with all financial and other
information concerning the Company as Vectis Group reasonably deems necessary or
appropriate in connection with the performance by Vectis Group of the services
contemplated by this engagement and in that connection will provide Vectis Group
with access to the Company's officers, directors, employees, accountants,
counsel and other representatives. The Company acknowledges and confirms that
Vectis Group (i) will rely solely on such information in the performance of the
services contemplated by this engagement without assuming any responsibility for
independent investigation or verification thereof; (ii) assumes no
responsibility for the accuracy or completeness of such information or any other
information regarding the Company; and (iii) will not make any independent
appraisal of the assets, operations or financial condition of the Company.

        (b) The Company will be solely responsible for any and all information
concerning the Company used in connection with the placement of the Securities
contemplated hereby and any and all other written or oral communications
provided by or on behalf of the Company to any actual or prospective purchaser
of the Securities (all such information and communications are hereinafter
referred to as the "Information"). The Company represents and warrants that the
Information will not, as of the date of the offer or sale of the Securities or
the Closing of any such sale, contain any untrue statement of a material fact or
omit to state a material fact required to be stated therein or necessary in
order to make the statements therein, in light of the circumstances under which
they were made, not misleading. The Company authorizes Vectis Group to provide
the Information to Qualified Prospective Purchasers of the Securities. If at any
time prior to the completion of the offer and sale of the Securities or the
Closing of any such sale an event occurs as a result of which the Information
(as then supplemented or amended) would


<PAGE>   3
Mr. David H. Hayden
March 29, 2001
Page 3

include any untrue statement of a material fact or omit to state any material
fact necessary in order to make the statements therein, in light of the
circumstances under which they were made, not misleading, the Company will
promptly notify Vectis Group of such event and Vectis Group will suspend
solicitations of Qualified Prospective Purchasers of the Securities until such
time as the Company shall prepare (and the Company agrees that, if it shall have
notified Vectis Group to suspend solicitations after the Company has accepted
orders from Qualified Prospective Purchasers, it will promptly prepare) a
supplement or amendment to the Information which corrects such statement(s) or
omission(s).

4.      Exemption from Registration; Offer and Sale of Same or Similar
Securities. It is understood that the offer and sale of the Securities will be
exempt from the registration requirements of the Securities Act of 1933, as
amended (the "Act"), pursuant to section 4(2) thereof. The Company will not
directly or indirectly, make any offer or sale of the Securities or of
securities of the same or a similar class as the Securities if as a result the
offer and sale of the Securities contemplated hereby would fail to be entitled
to the exemption from the registration requirements of the Act provided for in
section 4(2) of the Act. As used herein, the terms "offer" and "sale" have the
meanings specified in section 2(3) of the Act.

5.      Additional Restrictions on Company. In connection with all offers and
sales of the Securities:

        (a) The Company will not offer or sell the Securities by means of any
form of general solicitation or general advertising. The Company will not at any
time during the term of this engagement, or for a period of six months following
completion of the placement of the Securities contemplated hereby, make any
reference publicly to the transactions contemplated hereby, by way of the
issuance of a press release, the placement of an advertisement or otherwise,
without the prior consent of Vectis Group.

        (b) The Company will not offer or sell the Securities to any person who
is not an "accredited investor" as defined in Rule 501 under the Act.

        (c) The Company will exercise reasonable care to ensure that the
purchasers of the Securities are not underwriters within the meaning of section
2(11) of the Act and, without limiting the foregoing, that such purchases will
comply with Rule 502(d) under the Act.

        (d) The Company will not make any Form D or other filings with the
Securities and Exchange Commission with respect to the offer and sale of the
Securities without Vectis Group's prior written consent, except where in the
reasonable judgement of the Company or its counsel such filing is necessary in
order to comply with securities laws.

        (e) The Company will cause to be delivered to Vectis Group the same
opinions of counsel and accountants' letter agreements that it provides to
purchasers of the Securities.


<PAGE>   4
Mr. David H. Hayden
March 29, 2001
Page 4

        (f) The Company shall be deemed to make to Vectis Group all
representations and warranties which it makes to purchasers of Securities in any
purchase agreement or other document.

6.      Compliance with State Securities Laws. The Company will take such action
as is necessary to qualify the Securities for offer and sale under the
securities laws of such states and other jurisdictions of the United States.

7.      Indemnification. Since Vectis Group will be acting on behalf of the
Company in connection with its engagement hereunder, the Company and Vectis
Group have entered into a separate letter agreement (the "Indemnification
Agreement"), dated as of the date hereof, providing for the indemnification by
the Company of Vectis Group and certain related persons and entities.

8.      Termination.

        (a) The engagement of Vectis Group hereunder (i) may be terminated at
any time, with or without cause, by either the Company or Vectis Group, upon ten
days' prior written notice thereof to the other party and (ii) shall terminate
immediately upon the completion of the placement of all of the Securities
contemplated hereby.

        (b) In the event of the termination of Vectis Group's engagement
hereunder pursuant to clause (a)(i) above, Vectis Group shall be entitled to a
full Finder's Fee in the event that at any time during the twelve-month period
after any such termination the Company sells the Securities (or securities of
the same or a similar class as the Securities) to any Qualified Prospective
Purchaser which was contacted by Vectis Group in its capacity as a finder
hereunder regarding the placement of the Securities contemplated hereby. Within
fifteen days following any termination hereunder Vectis will confirm in writing
the Qualified Prospective Purchasers contacted by Vectis Group prior to any such
termination.

        (c) The provisions of Paragraphs 2, 7, 8 and 9 of this letter agreement
shall survive any termination of the engagement of Vectis Group under this
letter agreement and shall remain in full force and effect. Furthermore, no
termination of Vectis Group's engagement hereunder shall affect the Company's
obligation (i) to pay Vectis Group its Finder's Fee(s) or reimburse Vectis Group
for expenses as provided for herein or (ii) under the Indemnification Agreement.

9.      General.

        (a) In connection with this engagement, Vectis Group is acting as an
independent contractor and not in any other capacity, with duties owing solely
to the Company.


<PAGE>   5
Mr. David H. Hayden
March 29, 2001
Page 5


        (b) No advice rendered by Vectis Group hereunder, whether formal or
informal, may be disclosed, in whole or in part, or summarized, excerpted from
or otherwise referred to without Vectis Group's prior written consent.

        (c) This letter agreement supersedes any prior agreements,
representations or promises of any kind, whether written, oral, express or
implied between the parties hereto with respect to the subject matters herein.
This letter agreement, together with the Strategic Analysis Letter Agreement
dated as of March 29, 2001, the Advisory Services Letter Agreement dated as of
May 30, 2001, and each of the indemnification letter agreements, constitutes the
full, complete and exclusive agreement between you and Critical Path with
respect to the subject matters herein. This agreement cannot be changed unless
in writing, signed by an authorized officer of the Company and Vectis Group. The
Company has all requisite power and authority to enter into this Agreement and
the transactions contemplated hereby. This Agreement has been duly and validly
authorized by all necessary action on the part of the Company and has been duly
executed and delivered by the Company and constitutes a legal, valid and binding
agreement of the Company, enforceable in accordance with its terms.

        (d) The validity and interpretation of this letter agreement shall be
governed by, and construed and enforced in accordance with, the laws of the
State of California applicable to agreements made and to be fully performed
therein (excluding the conflicts of law rules). Each of the Company and Vectis
Group (and, to the extent permitted by law, on behalf of their respective equity
holders and creditors) hereby knowingly, voluntarily and irrevocably waives any
right it may have to a trial by jury in respect of any claim based upon, arising
out of or in connection with this letter agreement or the Indemnification
Agreement or any of the agreements or transactions contemplated hereby or
thereby.

        (e) The benefits of this letter agreement shall inure to the parties
hereto, their respective successors and assigns, and to the indemnified parties
hereunder (and under the Indemnification Agreement) and their respective
successors and assigns and representatives, and the obligations and liabilities
assumed in this letter agreement (and under the Indemnification Agreement) by
the parties hereto shall be binding upon their respective successors and
assigns.

        (f) The invalidity or unenforceability of any provision of this letter
agreement or the Indemnification Agreement shall not affect the validity or
enforceability of any other provisions of this letter agreement or the
Indemnification Agreement, which shall remain in full force and effect.

            [The remainder of this page is intentionally left blank.]


<PAGE>   6
Mr. David H. Hayden
March 29, 2001
Page 6

We are delighted to accept this engagement and look forward to working with the
Company on this assignment. If this letter agreement correctly sets forth your
understanding of the agreement between Vectis Group and the Company with respect
to this engagement, please sign and return to one of the enclosed copies of this
letter agreement to the undersigned. This letter agreement, when executed and
delivered by the Company, shall constitute a binding agreement between Vectis
Group and the Company as of the date first above written.

                             Very truly yours,
                             VECTIS GROUP, LLC



                             By   /s/ Matthew Hobart
                                -----------------------------------------------
                                               Matthew T. Hobart
                                 Managing Director and Chief Financial Officer

Accepted and Agreed to as of the date first written above:

CRITICAL PATH, INC.



By   /s/ David Hayden
  ------------------------------------------
              David H. Hayden
       Executive Chairman and Founder