run the test program <?phpinfo();?> and look for
Configuration file (PHP.INI) path +
extension_dir +
include_path
Mine were wrong and I had the same error message you have……
It indicates that that PHP can’t find the INI file. Open PHP.INI and read the note about this [about PHP.INI]. I set the environment varible PHPRC and everythings works as expected. THE [MySQL manual install] gives details about this setting.