The EZ Router THC looks like a Sound Logics THC http://www.soundlogicus.com/thc300a.htm Which is a repackaged version of Bob Campbells THC300
I know Sheetcam TNG has a post listed for Plasma THC 300. If your version of sheetcam doesn't have this post you can contact Les here: http://tech.groups.yahoo.com/group/sheetcam/ I'm sure he will be more than happy to help you.
I suspect part of your problem is BobCAD Try doing a simple geometric shape in BCC using only the CAD part of the software. Export the drawing in .dxf format. Open the test part in sheetcam & apply all CAM functions there. Lead in, speed etc. etc.
Then do your post processing to a .tap file open that in Mach & see what you get.
I bought V 21 BCC with all the Nesting & other bells & whistles in 2007. I struggled with it for many hours & finally gave up. To this date it is nothing but a paperweight to me. It seems BCC is one of those products that you either love or hate with a passion. I'm in the latter group. I'm not telling you it will not work. I'm sure it will if you want to spend the many hours it will take in the learning curve.
I have attached a AutoCAD .dxf file I know is good try to use it if you can.