I don't know the actual requirements, but every time I've done it I had DOD certificates, drivers, approvit, and pureedge or lotus.
Provided you have all this, and you are actually using the Adobe reader, I'm not sure what to tell you. If everything else works (AKO, Lotus, etc.) And just not pdf, it would sound more like an issue with your pdf reader. You could reinstall, upgrade or reconfigure.
As an alternative, LPS may provide an interim solution.