i can't offer any real assistance to your problem. I spent a few days looking into PHP connectivity with MSSQL and the best solution I came up with was to dump MSSQL and load MySQL.
Unless it's changed since I looked I read something about PHP not supplying MSSQL dll files any longer and to use some alternative. there's a few links in google that might help but honestly after 4 days of trying with MSSQL, i loaded MySQL and had MySQL and RoundCube running in about 15 minutes.
a quick and dirty way is to install
XAMPP apache, mysql, php (you can choose not to install filezilla and mercury mail transport).