I\'m working on a web project that is to be deployed on a 64bit Windows 2008 Server machine running IIS 7.5 and PHP 5.3.8. The database on the system is Microsoft SQL Server
The error you are showing for the SQLSRV driver implies the DLL is never loading. What does your php_info() say?
Also, do you have the SQL Server Native Access Client (SNAC) 10 installed? The SQLSRV driver requires it.