I've just switched from the hosting that is shared atmosphere to some devoted service and although testing my code I'm discovering that some PHP functions aren't available:

Fatal error: Call to undefined function mb_strtoupper()

I've full use of WHM and that i can recompile PHP with a lot of options. Being a new comer to this, I felt it's easier to leave the choices I am unfamiliar with his or her default setting.

PHPINFO() states I'm running version 5.2.9 and APACHE 2.2.

Have I skipped a choice in setting up APACHE - can there be something I have to switch onto gain full use of PHP functions?

this can be a question better requested on serverfault.com

however, relating to your version you moust likely have to activate megabytes extensions

also make certain your php is put together with --enable-mbstring