Okay, I figured out the issue. Your robots are too old. In this case your digger. It 'dies' before it can be properly disposed of leading to an immediate crash... I never tested into the aging logic of robots so this has slipped by over time.
I have a fix implemented on my end (https://github.com/ldicker83/OPHD/commit/3dde746df74076e03387ee6c1344aa452c2350f4) which will be in the next release of OPHD. Good catch! :D
(https://snag.gy/MkZyh2.jpg)
I attached an updated version of your save file with the robot age's reset to 0 so they'll be good for another 200 turns.
For anybody looking at a sudden crash around 200 turns or so, you can use the following method to update your save files to reset your robot's ages back to 0. It's purely a band-aid workaround that is fixed in the next release:
Open up your save game file in any text editor (notepad++ is my recommendation as it handles newlines properly). Look for similar lines near the very bottom of the file:
<robot id="2" type="1" age="195" production="1" x="37" y="80" depth="4" direction="5" />
For each robot, change the field age="XXX" to age="0". Your ages may vary but this defect is related to improper handling of 'dead' robots. If this doesn't fix your crashing, please open up a new thread with as many details as you can provide to replicate your issue.
As a final aside, I split this thread into a new topic with an updated title.