U S B being used by other app

Hi, I am trying to get parallels to connect to my Aten usb to serial adapter. but everytime I try to select it I get a message saying the device is being used by another app. Please HELP!!!!!
here's my info:
Mini Mac 2.0
2gig ram
120 hdd
10.4.10
Parallels build 5160 (fresh install from disk)
Parallels tools installed
Windows Xp Home edition SP2
Error mesage reads;
"USB device you are trying to connect to the virtual machine is being used by another application. Close that application or unplug the device and plug it again. Then try to connect the device again."
The device shows up as: Aten International-UC-232A Serial Port [pl2303]

I guess that's about it except to say I've been working on this one for 2 days now and at my wits end. Need some advice desperately!

 

Hello,

please, check this article. It's the most common solution for this issue.
There's also this thread which also can be useful.

Best regards,
Alicia.