Ntrack and Jamstix

This combination used to work quite nice for me (both Jamstix 2 and 3), but now it doesn’t seem to be any good (must be more than one year since I last tried it). It just freezes after a short while, and ntrack has to be restarted. Sometimes it freezes when I start playback from ntrack, sometimes when e.g. trying to load a kit or style inside jamstix. Anybody else using jamstix and ntrack? Any ideas for solving the problem? I did try downloading an older version of ntrack, but that didn’t help.