On my T3 (not T5) it gets fatal exception if I ALSO had Phone Link Update (#2 - 11/29/04) installed.
If it's easy to hard reset and restore, then I suggest doing that. Sorry if I sound like PalmOne support. 
Frst thing after reset load keyboard driver and you should see that it works. Then restore things carefully to find conflict. I've found it's easiest to restore from SD if you own a backup program. What I do is restore by the letters - letter A, test if things are okay, then letter B, etc. (letter A means restore apps/DBs that start with letter A in the backup set).
Please note that hard reset erases data!!!
