Hi! I had once the same problem - can't load CHDK when had some photo on SD. But it's not really random - I saw, that this happened with one image as the last, but after shot another one, the problem gone. Unfortunetly I didn't keep this image. Another time I'll keep the photo cousing the problem.
In addition: I've got 1.01c firm and CHDK from #136. SD: 8GB, 1 partition, CHDK run through Firm Update. Zebra disabled, not remember about Edge, possibly the bracketing was enabled, but it has been enabled before. Rather no other overrides.