I've tried your new script. I've a trouble that i already had before with your first scrip , but now it's stronger.
My first tests was with 1 shoot / 5s. The scrip was sometimes crashing after 11 shoots. when it was (often) working, the ixus worked for 2h by -25°C in fridge (with light for exposure shutter).
I'v tried with 10 s and 7s. It always crash after few shoots. So i've tried again with your last script with 10 s and it always crash too.
In addition to reyalp's comments, I'd like to suggest that your problems are most likely not related to the script. To prove or disprove this, please rerun your refrigerator test using the simple
interval.lua script that comes with CHDK at a 10s interval and see what happens.
(
Edit : there may be a clue in your description. When you shoot quickly, the camera uses more power and stays warmer. When you slow down the shot rate, the camera will draw less power. As all the power drawn essentially ends up as heat, drawing less power means that the camera gets colder. As a temperature of -25 deg C is well outside of the camera's operating range, this might be significant.)
