as far as i can make out, these are created when you run windows update, the numbers relate to the hotfix entries in Add/Remove programs and may be required if you choose to uninstall a hotfix.
best to leave alone if you have enough space.
if you are short of space, see if you can compress them into a new folder or maybe write to cd.
if you delete them, you wont be able to uninstall the hotfix's.
if your system is stable then you could probably get rid (but i would keep a copy on cd just in case)