What did you root with? Some of the software has what security calls trojans. Is it possible that your security shut down/blocked the connection somehow thinking it was on the phone?
What happens if you try another computer?
I've had crap like this with older HP printers and USB ports.
Can you see what's on the card if you use a reader?
I can plug into a Linux box and see the drives. I am also using XP and can see the drives.
I just updated to Gingerbread. PITA with a few files.