Adobe Reader 9.0 display problem on .pdf files

We installed adobe reader 9.0 in our terminal services environment on WIN 2003. Our TC7020 thin clients display the .pdf file in large blocks, the characters are overlayed with a video block. If we expand the document image to 125% or more, then the blocks go away. We dont have this problem on the PCs or on the PCs in Terminal Services, so we’re thinking the problem is in the Thin Client. We’ve looked for a patch for the video drivers and cant find one? The Thin Client resolution is set for 8bit?
I found an article that said Adobe Reader 8 & 9 have the same problem? I could downgrade to Abode Reader 7?
If anyone else has had this problem and found a solution, please let me know.
Thanks!