1> If you are using PHP3 then uncomment (no semicolen) the phrase which points to PHP_MySQL.DLL file to be used... (sorry, donno the exact statement there.)
2> If its PHP4 that you'r using, then let that phrase be commented, coz MySQL support is already present.
If it does'nt help, let us know here, in PHPBuilder.
Regards
JoJo