I'll have to agree overall with TB0ne... We need a bit more information.
I myself have been able to get Mandrake/Mandriva working in various VM environments. Although I must say, VMWare Fusion is sooo much better than Parellels. I'm a MacBook Pro user myself, and I've tried Parellels and in comparison, it sucks. But thats a discussion for another time.
First off, what is the error message you are receiving? Are you using the x86 images of Mandriva? The MacBook Pro's Core2Duo uses native i386 architecture, not IA64 like some think they do.