I have had this problem before too but I can't remember what I did to fix it. I want to say I only had it trying to set things up on a windows box.

Are you only getting text on the screen? No banners or anything?

If it is only text on the screen with no formatting then it isn't reading the options file. Maybe a permissions error? It does seem that it is only reading the html of the file and not parsing the php. Even if the MSSQL wasn't setup and working it still should be parsing the php. I know very little of IIS but I know when I tried to get it running on that platform I had a hard time with permissions.