Cannot save in Preview - don't have "permission"

Bumped to add that I changed permissions (me: read and write, everyone: no access) and that seemed to work...at first. Now I'm getting the error again, but it occurs sporadcially; sometimes I'll have an error, sometimes I won't. Can't figure out why.

It gives me the option to "duplicate", and I have tried that, and that seems to work OK. However, I shouldn't have to do this though, and I never had this issue until upgrading to Lion.

I did an experiment. I saved some random image from the internet onto my desktop with no problems. I opened it up with Preview and cropped it. Saved with no problems. It seems like only screen capped images (Command+Shift+4, to be precise) cause this problem in Preview. Oddly, I can open them and edit them fine in Paintbrush. (Although Paintbrush pulls up all the images that I recently edited, but that's a different issue altogether.)

Another problem with Preivew (as well as Pages) is that I don't have an option to "Save" or "Save as". It's always "save a version." Well, I don't want to save a version! I want to save like how I USED TO.

Any help with this would be greatly appreciated; as you can tell I'm pretty frustrated!

Bump. This is still an issue.