iWork pages, numbers - not see words ...

MB = intel dg31pr
VC = ati radeon sapphirehd 2400 pro
Lan Card = rtl8139d
iDeneb - Osx 10.5.8

Hi everybody,
I have a really big problem with Pages and Numbers, buyed in volume license.

When I open pages or numbers, the editing window is blank, and if i Click on it, nothing happend.

If I select all, and change font or other, noting appare, but the changes daoes. I can chek it by print as pdf and opening the file with preview application.

I can't understand why!

( I Download the trial version and than input the serial number, and than downloaded the upgrade and installed it).


Could somebody help me please?
Thanks

Ennio