USB Device worked in 3.0 not enough memory in 4.0. Any Fix?

I had previously used Parallels 3.0 and was able to use a specific USB device. I found it a little unwieldy but it worked. I purchased a new Mac Mini with double the memory and faster processor and upgraded to Parallels 4.0. The device is recognized by the application but when I try to use it I get a message that I have insufficient memory and the process quits. Can I increase the memory? What else can I do to resolve this? Thanks.