There is(?was) a bug in Ubuntu Feisty Fawn which prevented me from auto mounting my USB drives. I was having this problem for sometime in UbuntuStudio, and I was thinking it was specific to that. But when I installed Feisty recently I had the same problem. (I know Gusty is just about to release…) So i found this after bit of a deep search, that fixed it right up.
Its just one line of code, that worked:
sudo modprobe -r ehci_hcd
Don’t know what happened nor how long the fix will last. I found this solution from here, so refer here for more details from here.