Document:

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                                                                    Exhibit 10.4

August 8, 2007

[INVESTOR NAMES]

Dear Investors:

         Reference is made to that Stock Purchase Agreement, dated as of August
8, 2007, among Narrowstep Inc., a Delaware corporation (the "COMPANY") and each
of you (the "PURCHASE AGREEMENT"). Capitalized terms used but not defined herein
shall have the meanings ascribed to them in the Purchase Agreement.

         As an inducement to the investors who purchase Securities pursuant to
the Purchase Agreement, the undersigned hereby agrees that from the date hereof
and continuing for a period of nine (9) months thereafter (the "LOCK-UP
PERIOD"), the undersigned will not (A) offer, sell, contract to sell, pledge,
hypothecate, transfer or otherwise dispose of, directly or indirectly, any
shares of capital stock or other equity securities of the Company (including
without limitation any shares of capital stock or other equity securities issued
or issuable to the undersigned as the result of any stock split, stock dividend
or distribution on such securities) and any options, warrants or other rights to
purchase or acquire shares of capital stock of the Company, in each case whether
now owned or hereafter acquired (the "LOCK-UP SHARES"), (B) enter into any
agreement or transaction that would have the same effect, (C) enter into any
swap, hedge or other arrangement that transfers, in whole or in part, any of the
economic consequences of ownership of the Lock-Up Shares, whether any such
aforementioned transaction is to be settled by delivery of the Lock-Up Shares,
in cash or otherwise, or (D) publicly disclose the intention to make any such
offer, sale, pledge or disposition, without, in each case, the prior written
consent of investors who purchased a majority of the Securities issued pursuant
to the Purchase Agreement.

         Notwithstanding the foregoing, the undersigned may transfer Lock-Up
shares (i) as a BONA FIDE gift or gifts, provided that the donee or donees
thereof agree to be bound by the restrictions set forth herein, and (ii) to any
trust for the direct or indirect benefit of the undersigned or the immediate
family of the undersigned, provided that the trustee of the trust agrees to be
bound by the restrictions set forth herein, and provided further that any such
transfer shall not involve a disposition for value. For purposes of this
Agreement, "immediate family" shall mean any relationship by blood, marriage or
adoption, not more remote than first cousin.

         In furtherance of the foregoing, the Company shall, and shall cause its
transfer agent and registrar to, decline to make any transfer of the Lock-Up
Shares if such transfer would constitute a violation or breach of this letter
agreement.

         Each of the signatories hereto acknowledges that each of the investors
who purchased Securities pursuant to the Purchase Agreement are third party
beneficiaries of this letter agreement and this letter agreement may not be
modified or changed without the prior written consent of the investors who
purchased at least a majority of the Securities issued pursuant to the Purchase
Agreement.

         This letter agreement shall be binding on the undersigned and the
successors, heirs, personal representatives and assigns of the undersigned. This
letter agreement or the rights hereunder may not be assigned by the investors
named above, except to their respective partners and affiliates to which they
transfer all or any portion of the Securities in accordance with applicable law
or regulation.

                                       Very truly yours,

                                       Signature:
                                                   -----------------------------
                                                    David McCourt

ACKNOWLEDGED AND AGREED:

NARROWSTEP INC.

By:
   ---------------------------------
Title:
      ------------------------------<PAGE>

                                                                    Exhibit 10.5

                         AMENDMENT AND WAIVER AGREEMENT

      AMENDMENT AND WAIVER AGREEMENT (this "Agreement") is made as of the 3rd
day of July 2007, by and among Narrowstep Inc., a Delaware corporation (the
"Company"), and the holders set forth on the signature pages affixed hereto
(each a "Consenting Holder" and, collectively, the "Consenting Holders").

                                    RECITALS

      A. The Company has issued $7,110,000 in aggregate principal amount of its
12% Mandatorily Convertible Notes (the "Notes") and warrants (the "Warrants") to
acquire up to an aggregate of 3,555,000 shares of the Company's common stock,
par value $0.000001 per share (the "Common Stock"). Capitalized terms used
herein have the respective meanings ascribed thereto in the Notes unless
otherwise defined herein.

      B. The Notes are mandatorily convertible at a 10% discount into the
securities issued by the Company in a Qualified Financing.

      C. Upon consummation of the Qualified Financing, the Company anticipated
that the holders of the Notes (the "Holders") would enter into the Qualified
Financing Documents used to effect the Qualified Financing, which would include
customary registration rights provisions requiring the Company to register for
sale under the Securities Act of 1933, as amended, and applicable state
securities laws, the Common Stock received by the Holders upon the mandatory
conversion of the Notes, the exercise of the Warrants and the exercise or
conversion of any other equity-linked securities received upon conversion of the
Notes (the "Registration Rights").

      D. The Company has requested that the Consenting Holders irrevocably waive
their Registration Rights (the "Waiver").

      E. In order to induce the Consenting Holders to grant the Waiver, the
Company has agreed to amend the Notes as provided herein.

      F. Under the terms of the Notes, the Majority Holders have the right to
waive and/or amend the terms of the Notes on behalf of all the Holders.

      G. The Consenting Holders constitute the Majority Holders.

      In consideration of the mutual covenants contained herein and other good
and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, and intended to be legally bound, the parties hereto hereby agree
as follows:

      1. Each Consenting Holder hereby irrevocably waives its Registration
Rights, such Waiver to be effective only upon the consummation of a Qualified
Financing.

      2. Effective as of the consummation of a Qualified Financing, each of the
Notes is hereby amended as follows:

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            (a) The definition of "Qualified Financing Documents" in Section 1
of the Company Notes is hereby replaced in its entirety with the following:

      "Qualified Financing Documents" means the definitive documentation entered
      into by the Company and the investors in connection with the Qualified
      Financing, excluding any provisions providing registration rights to such
      investors.

            (b) The second sentence in Section 4(a) of the Company Notes is
hereby replaced in its entirety with the following:

      "Upon the occurrence of a Mandatory Conversion Event, all of the principal
      amount of this Note and any accrued and unpaid interest due hereon shall
      automatically and without any action on the part of the Holder convert on
      a dollar-for-dollar basis, less a discount of 10%, into Conversion
      Securities; provided, however, that if a Mandatory Conversion Event occurs
      on or prior to March 2, 2008, the interest accrued hereon shall be
      calculated as if the Mandatory Conversion Event occurred on March 2, 2008
      and this Note remained outstanding until such date."

      3. Except as expressly provided herein, the Notes shall continue to be in
full force and effect.

      4. This Agreement shall be governed by, and construed in accordance with,
the internal laws of the State of New Jersey, without reference to the choice of
law principles thereof.

      5. This Agreement may be executed in counterparts, each of which shall be
deemed and original and all of which together has constituted one and the same
instrument.

             [THE REMAINDER OF THIS PAGE LEFT BLANK INTENTIONALLY]

                                     - 2 -

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      IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed by the undersigned, thereunto authorized, as of the date first set
forth above.

                                                NARROWSTEP INC,

                                                By: /s/ Lisa Van Patten
                                                --------------------------------
                                                Name: Lisa Van Patten
                                                Title: Chief Financial Officer

                                     - 3 -

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Principal Amount of Notes: $                    OMNI CAPITAL, LLC
                                                --------------------------------
                                                      (Consenting Holder)

                                                By: /s/ ARUN NETRAVALI
                                                --------------------------------
                                                Name: ARUN NETRAVALI
                                                Title: MANAGING PARTNER

                                     - 4 -

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Principal Amount of Notes: $                    W. INVESTMENT PARTNERS V
                                                --------------------------------
                                                      (Consenting Holder)

                                                By: /s/ MICHAEL DATES
                                                --------------------------------
                                                Name: MICHAEL DATES
                                                Title: MEMBER

                                     - 5 -

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Principal Amount of Notes: $                    JOHN L. STEFFENS
                                                --------------------------------
                                                      (Consenting Holder)

                                                By: /s/ JOHN L. STEFFENS
                                                --------------------------------
                                                Name: JOHN L. STEFFENS
                                                Title:

                                     - 6 -

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Principal Amount of Notes: $                    BARRY S. STERNLICHT
                                                --------------------------------
                                                      (Consenting Holder)

                                                By: /s/ BARRY S. STERNLICHT
                                                --------------------------------
                                                Name: BARRY S. STERNLICHT
                                                Title:

                                     - 7 -
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Principal Amount of Notes: $                    ROGER L. WERNER, JR.
                                                --------------------------------
                                                      (Consenting Holder)

                                                By: /s/ ROGER L. WERNER, JR.
                                                --------------------------------
                                                Name: ROGER L. WERNER, JR.
                                                Title:

                                     - 8 -
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Principal Amount of Notes: $                    DAVID C. MCCOURT
                                                --------------------------------
                                                      (Consenting Holder)

                                                By: /s/ DAVID C. MCCOURT
                                                --------------------------------
                                                Name: DAVID C. MCCOURT
                                                Title: CHAIRMAN & CEO

                                     - 9 -

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