Error while trying to parse an Image

[tina2]

I have upgraded some of my users for Acrobat Reader 4.0 to 5.0. On certain documents, the users who have 5.0 get the error message "... Error while trying to parse an image".
When I open the document in 4.0, it opens fine. the common deniminator is that all of the documents in question have markings on the (i.e. handwriting or staple marks) Why cant version 5.0 recognize these? Am I missing a driver or something?

Thanks,
Kristine