what xampp version you use?
if u have sql 2008 server for DB
u must use 1.7.7 xampp version
then after installed go to htdocs\php\php.ini search for 'mssql' and first result remove ; to enable the extension.
then download DLL4XAMPP.exe (google it) and install it by clicking it twice.
then restart apache (stop and start)
then try again to install web.
Proglem sql 2008 my delete 2008 . Setup sql 2000 proglem 0 tenx king