The MPLAB version should not matter at all. MPLAB itself is just an editing tool. I've run with older and newer versions.
What would matter is the mcc18 toolset version that MPLAB is running for us. That should be version 2.4 in any case.
Kevin originally developed his CMUCAM code on an EDU, a precurser to Vex, so it will work. You're having some sort of conversion problem, but it sounds like you worked around it.
You can checkout our
workshop Vex code if it helps any. Probably look about halfway down the page.
We didn't use the Vex version 7 code as a starting point though.