Have you tried versiontracker? sometimes you can download from there when macupdate has a hiccup.
BTW, I am not 100% sure that 1.3 in Panther is as rock steady as earlier versions were in 10.2. I had one problem, so I am laying off until the next upgrade. Other people may have had none, and swear by it. Just my experience.
Had to hard reboot after doing an operation in it, and I didn't like that although no damage was done.