TMV example in FREALIGN

Hi, I have download frealign_v8.11 and try to do the helical example in the extract folder examples/helical_refinement. When I didn't modify anything, it works, just run 1 iteration.But when I revised tha end_process to 5, something went wrong. It has run 2 iterations successfully, from the 3nd iteration, it will have a message saying "segmentation fault". Also the same situation for my own data. So what should I do to let it run smoothly? Thanks!