Midiman Midisport 4x4 USB freezes

Hi
I have purchased a Midiman Midisport 4x4, the blue and yellow one.
My system runs on a XP SP2 but I couldn't install the XP Sp2 drivers and went with the XP drivers. I have a m-audio 410 soundcard and the setup kept stopping because it stated "another m-audio device is connected" even after I disconnected and uninstalled it.
I have a USB midi keyboard and use Sonar 5. I routed the midi cable through the midiman to one of my hardware synths (Yamaha CSR6, Roland JV 1010, Virus...etc I ended up trying them all) Every time the midiman freezes after I play just a few notes. Playing the notes one by one seems to last longer but a chord or a signal from the sequencer freezes the midiman. It seems the data flow through the midiman might be the problem, although midi is old and slow. I have tried every thing I could think of: Installed the driver many times over. Tried the 2x2 driver. I have also switched the "allow windows to shut down usb device" in the USB root hub menu off. I have fiddled with the asio buffer settings, still no success.
My system is newly formated and everything runs perfect. There are also no resources problems as I don't use this computer for anything else and midi is such an old standard it works even on my zx spectrum.
Thank you very much for your time
Mihai