HELP Keyboard !!!My USB MIDI INTERFACE UM-2ex Edirol is not functioning properly..?

It somewhat works on and off.. And It takes forever before it decides to just start working again.. My windows xp proffessional will recognize the Um-2 New hardware.. But the light won't come on.. and the prompt comes up to "install the software automatically" but when I press that(next) it says " THE hardware was not installed because the wizard cannot find the neccessary software.. But the weird thing is like i said,, sometimes the light does come on and my midi interface does work... SO I really Need some Help or ADVICE.. THANKS !!!