I own a SAPPHIRE Pure White Fusion E350M1W motherboard with AMD APU e350 (Zacate).
When I installed the Ubuntu 13.04 via a USB pen drive, I rebooted the PC then I got this error:

GRUB loading:
Welcome to GRUB!

error: file '/boot/grub/x86_64-efi/normal.mod' not found
Entering rescue mode...
grub rescue>

I get the same error installing Debian Wheezy RC1.

How to solve it?

Regards,

Cooper