Jim7511,
Sounds like you are hitting a software limitation of the machine in terms of the maximum radius size. Have you called Mits about this (maybe there is a parameter that can be changed to help prevent the error)? If you cannot modify or change the geometry, there might be another way to "cheat" this. You can process the geometry as a 4-Axis program using the same geometry for the Top and Bottom profiles (no taper will be machined). This will output a giant program with all small G1 X__ Y__ segments, but might be an easy work-around for your problem.
-Brian