One solution I learned to overcome a 'not so straight saw guide, is to attach a hardwood slat along the guide edge (typically 3/4'thick). While the is a very slight flex to hardwood, the tolerance should be acceptable. Also want to slow your cutting speed so as to not put undue pressure sideways into the guide.

I heard that the rod that it rides on, may be bent. This is the rod, that you normally adjust, to get your straight cut, parallel to the blade. One mans solution was to turn the rods, so the bend of the rod, was vertical, rather than horizontal. You may want to look into ordering new , hopefully straight rods, from QEP too.