So when you type 'lsusb' with the device inserted, you get no output at all? That's very strange.
The bit in dmesg about being "unable to enumerate USB device" is interesting. I found this bug report which seems to be related to the issue. It seems to have been introduced in Intrepid. Unfortunately there's no clear answer there, but at least they're aware of it.
It may help to run this command before plugging the device in:
then plug the stick in; does it help?
sudo modprobe -r ehci_hcd
I think that your problem ultimately has to do with your USB drivers, not your wireless card. Have you had any other trouble with USB devices since upgrading to Intrepid?