I'm happy to say that this is fully repeatable behavior on my camera... 
It ran ok all night (740 shots) in my test. A570 IS 1.01A build 491
does anybody have the build 488 for a570 1.01 for me to test?
Also, could you please test again with build 491?
Hm well I've almost given up on this version of the script... this time it did a lot of weird things. I restarted it twice last night. First one due to the crash, second one most likely due to battery low, third time it probably to battery low as well since the log file just ends to "Frame 344 taken at 03:15:36".
So it didn't crash to mem full that last time.
This time I used MF without CHDK shortcut and a video plug. I zoomed in some, but forgot to zoom in after changing the batteries. So, I have 3 sets of images.
The first set seems ok (white balance is no good but that's not the script's fault), although it started with severe overexposure and then adjusted to a better exposure gradually (M mode settings were set for proper exposure at startup for this first set). It was not dark yet when I started it the first time.
The second set started when it was dark already. It took a few shots to increase exposure and when after it did that, it went berserk. One shot underexposed, one shot properly exposed, one shot underexposed etc etc, sometimes a few proper shots in a row. Also, the second set was entirely out of focus. It was windy so trees should be blurry, but buildings aren't in focus either.
For the third set I forgot to zoom in. Focus is OK. For an hour or two it seems to have worked perfectly, then it took a a couple few severely underexposed shots between good ones and then it started to toggle between good and bad shots like in the second set.
