[Coco] Drivewire 4 having trouble detecting my serial port

[Fred D. Provoncha]

I'm trying to set up Drivewire 4 on my Ubuntu Linux laptop to 
communicate with my Coco. I'm running the Drivewire 4 configuration 
program on my Ubuntu 12.04 Linux laptop. The laptop does not have a 
built-in serial port, so I'm using a USB-Serial adapter to connect it to 
my real Coco 3. According to my system, the adapter is being assigned to 
port "ttyUSB0". But within the Drivewire 4 setup program, underneath 
where it says "Drivewire has detected the following ports:" nothing 
shows up. Further down, it asks, "If Drivewire does not detect your 
serial port, you can enter the name below". I then type in 
"/dev/ttyUSB0" in the space provided and then click "Add Port". A 
message then appear saying: "/dev/ttyUSB0     This port does not exist". 
I know for a fact it does exist however, as it appears in the /dev 
directory in my Linux file system. Any ieas?

Thanks,
Fred Provoncha
Stansbury Park, UT