Spotnik

I have a number of PDFs I cannot open in Acrobat Reader 2.0. I get an "Unknown Filter" message. I cannot find anything at the Adobe site that explains why this is happening or how to correct it.

Most PDFs do not have this problem, and so far the only the only ones that have were downloaded from www.textkit.com, a library of Greek and Latin study resources. The files open fine on the desktop, regardless of version. I had problems with these files under Pocket PC 2002/Acrobat Reader 1.0 as well, and I was hoping the upgrade would solve it. No such luck.

Any suggestions?