SQL error [0xC3EC79FB] on Office Communicator Server 2007

For Office Communicator, you will need 2 servers, you cannot install SQL on office communicator and get away with it, you need the frontend and the backend. Maybe and I say "maybe", you  can get away with installing a SQL instance on a client machine, then  the Office Communicator on the server machine.
Here is what MS wrote for this error:

"The Office Communications Server 2007, Back-End Database, stores user data for all Enterprise Edition Servers within a pool. As a centralized repository, the Back-End Database cannot be installed on the same computer as any other Office Communications Server role. The Back-End Database cannot reside on an Enterprise Edition Server in the pool.

The Back-End Database is created automatically when you create the pool, but the computer that you designate as the back end must already be running SQL Server in order for installation to succeed. Before you deploy Enterprise Edition Server, install SQL Server 2005 with Service Pack 1 (32-bit or 64-bit) or SQL Server 2000 with Service Pack 4 or higher on a dedicated computer that meets the hardware requirements described in Infrastructure Requirements and Prerequisites in Microsoft Office Communications Server 2007 Enterprise Edition earlier in this document."