I tried to update after re-installing to try and get to the latest version of Safari 4 (whichever number that was) and was told that there were no software upgrades available!
I wondered whether that was because the Apple site was detecting that I had previously downloaded Safari 5 - because it didn't even offer me that!
It may be linked to the other posts on this thread - ie) that there are no longer any links to download Safari 4, which do not re-direct you to Safari 5.
But whatever the position is - I am far better off than I was with a completely malfunctioning Safari 5!
Sorry I can't be of more help on that one.
I think its because you have a Safari 5 download receipt still on your comp. This will make software update think you still have 5 installed. Not sure where they are located but you need to trash the file.