I do not know what that error in UP2Date means. I gave up on up2 date a while back when RedHat changed the signature file or whatever they did.
You may have an alternative update program installed call APT. Advanced Package Tool I think. To use it, go to prompt and type:
This will grab RPM headers for files you need updated. Wait til its done then type:
Answer Yes to permission question.
This will install packages for you. You must be root to use APT. APT is availible for download if you need it from freshmeat.org. Oddly enough, after you use APT and get all your updates, the Up2Date icon on the tool bar will turn back to the blue checkmark you expect.