I use a seperate program to cut from Corel X-3 called Sign Tools 3 and there is also one call I believe Cocut. Other than that I don't know of any other way. There is a guy on another board I go on who goes by the screen name FLUID and I will say If there is a way he would know. You can also try this board www.unleash.com you may find some help there.
Not sure about the Graphtec, but I used to do this all the time with my Roland CAMM1; cut directly from Corel (using the Roland-supplied driver), and X3 was the latest version I did this successfully with. On the Roland models, I never had any luck using the LPT (parallel) connection and always (since 1988) used the COM (serial) connection, but you ABSOLUTELY require either the correct Roland cable (XYRS-64) or a null-modem cable; the pin-out on a 'regular' serial cable isn't correct. This sounds as though this could be your situation now.
PS... just noticed this is your first post, so bonjour de Montréal and S101