Waiver of Redemption Rights Agreement between Essential Group, Inc. Shareholders and Silicon Valley Bank (August 25, 2005)

Exhibit 10.4

Dear Mr. Clarkson:

We have been advised that Silicon Valley Bank (“SVB”) is providing an asset based line of credit with a maximum credit limit of $6,000,000 (the “Loan Facility”) to Essential Group, Inc. (the “Company”) pursuant to a Loan and Security Agreement (together with any related documents or any other borrowing facility in place at SVB, the “Loan Documents”).

In order to induce SVB to provide the Loan Facility to the Company and to enter into the Loan Documents, each of the undersigned hereby agrees, that during the term of the Loan Facility and at any time any amount is outstanding under the Loan Facility or owed to SVB by the Company under any of the Loan Documents, and for a period of 30 days thereafter, the undersigned shall not vote any shares of Series A-2, A-3, A-4, A-5 or A-6 Preferred Stock of the Company, beneficially owned or controlled by them, directly or indirectly, now or hereafter (the “Shares”), to require the Company to redeem any shares of the Company’s preferred stock pursuant to the Company’s Amended and Restated Certificate of Incorporation and the Certificates of Designation, Preferences and Rights of the Company’s preferred stock or otherwise conduct or cause any action which may result in such redemption. Each of the undersigned further agrees that if it sells, assigns or transfers its Shares, prior thereto it shall legend its Shares with evidence of the restrictions created by this letter agreement and, as a condition to such sale, assignment or transfer, the undersigned shall require the purchaser, assignee or transferee to unconditionally agree in writing to be bound by the terms hereof.