You are correct - I tried uninstalling Reader XI and reinstalling Reader X and I was not able sign the document that way either. I apologize; I did not verify the reports I was getting from my end users before I posted.
Now, if I wanted my users to be able to e-sign instead of using digital signatures, would I still be able to protect the document from changes? I don't know much about the e-sign option, but it sounds like it might be easier than creating digital signatures for everyone; I just want to make sure we'll still be able to protect our forms if we do that.
Thank you again!