Don't know if this helps. I am using my own CHDK version with a little tweaks, I built the last one this morning.
I am working with two cameras, and I know that both of them had problems to start several times. Now I rebuilt the same version I used today, this time keeping the main.bin.dump, it is attached together with the ROM logs of both cameras.
If this doesn't help I'll try to reproduce the error again, at the moment it seems completely gone, although I am trying very hard. I am afraid it isn't.
Thank you very much, I really appreciate your help!