Don't know the program, so couldn't really tell ya. Here's some tips on what to look for though:
Look in the program settings for anything about a bounding box or a weeding box, as that sounds like what it may be doing.
If you're using fonts that are stretched out of proportion in applications like CorelDraw, you may need to convert them to curves before exporting. On my Versacamm it will eat up extra vinyl and sometimes make the image too large to fit the material unless I convert it curves beforehand.
Other things to check for would be to go to a wireframe mode if available and see if there's any way to remove the extra box, as sometimes when programs import vector designs they do flakey things like that.