I have had the same problem with the path list dragging and crashing. I was using 3ds Max 2012 on Win 7 64bit, Growfx Version 1.9.0. After troubleshooting it for a good while, I couldn't find any pattern in the crashing. Sometimes it crashes, most of the time it does not. I've tried changing display types from lines to meshes, applying modifiers, changing what path distributes on other paths... No pattern. Just occasionally it crashes. However in my casual experience with the problem, it did occur primarily when putting the path in the middle of the stack, rather than the top or bottom, as Ajroane explained.
Hope this helps.