[LAU] Phasex. Unable to start MIDI thread, then segfaults

This is phasex-0.12.0-beta4 on archlinux. It compiles ok, but fails to start with the following output when run from the command line. djmons@myhost ~]$ /usr/local/bin/phasex -d Raw Waveform '/usr/local/share/phasex/sys-samples/juno_osc.raw': 2809 samples Raw Waveform '/usr/local/share/phasex/sys-samples/juno_saw.raw': 5629 samples Raw Waveform '/usr/local/share/phasex/sys-samples/juno_square.raw': 5634 samples Raw Waveform '/usr/local/share/phasex/sys-samples/juno_poly.raw': 2814 samples Raw Waveform '/usr/local/share/phasex/sys-samples/vox_1.raw': 1193 samples Raw Waveform '/usr/local/share/phasex/sys-samples/vox_2.raw': 706 samples Initializing JACK client from thread 0xb71426c0 Unique JACK client name 'phasex-01' assigned. JACK is running with realtime scheduling. JACK sample rate: 44100 Internal sample rate: 44100 JACK requested sample rate: 44100 JACK output buffer size: 1024. Unable to start MIDI thread. Segmentation fault [djmons@myhost ~]$ Anyone know what the "Unable to start MIDI thread" bit means, and how I might resolve the problem? Nigel.