I don’t know if this helps, but the 2x2’s driver is hell to install. My uneducated guess is the driver is your problem. Try uninstalling and re-installing the MidiSports driver.
I agree with Mark; you should un- and reinstall the driver.
One other PITA is that it doesn’t seem to like to work properly if it is plugged in on startup. So, turn your comp on, THEN plug it in, and see if that works.
Time for a MOTU or even Edirol interface, I reckon…
I saw an interesting article in one of the electronic music mags the other day. It stated that some usb and or/firewire ports won’t accept full contact when plugged in because of the thick molded shielding at the ends of the cables. They suggested getting an Exacto knife and cut off about 1/4 inch of that molding. Be careful not to sever the cable protecting the wires.
After I got a new computer I had up the size of the low level output buffers in MIDIOX or it would fail updating my Little Phatty. You also might try to update the drivers on you Midisport