As I told in the OP, Instruments quits. No crash report in console app. I checked again. No messages in syslog as far as I could tell.

Instruments is quitting. The application keeps running. I have tried to run either Time Profiler or Leaks, with time profiler Instruments quits after 2-3 seconds. with Leaks I get past the first 10 seconds and get a green check mark and 2-4 seconds later Instruments quits.