Comment 5 for bug 322748

This device is based on a Prism chipset, which has a native Linux driver.
The ST121g USB IDs were added to the driver one year ago, but maybe it has not made it to Ubuntu yet?

You should try loading the appropriate module with "modprobe p54usb".
You may also try "modinfo p54usb" and see whether the ST121g USB IDs (06b9:0121) show up.
Or else someone should add the following patch to the Ubuntu kernel:

http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.32.y.git;a=commitdiff;h=878e6a432f85690a2c0d88d96f177e54ff1d4a57