I got almost the same problem..
I use Copam CP-2500 bundled with Artcut 2009 software, using usb cable (I use laptop, so it's the only way to connect with the machine)...
I've installed FTDI driver and artcut software, but when i'm going to cut, appear notification said error with com port...
Then i tried to install SignTools 4 trial, i set with recommended parameters, it goes nothing but printing queue...
I also tried to use SignGo, SignBlazer, SignCut... but result the same... this really frustrating... :'(