Multiple critical errors while saving

[General Patton]

Alice has been consistently screwing up the saves after making certain edits. By using backups and making new saves after small incremental edits, I managed to track down one of the points after which things go to hell when saved.

Here is the program right before the final bug-inducing change
ZombieSlayerDebug2.a2w

To make it crash, just go to Knight.Run and in the If statement, right after Knight.GainXP (StatIndex=1, Gain=1), put a Knight.GainXP (StatIndex=2, Gain=Knight.Encumbrance%). Saving will then fail catastrophically.

Here are screenshots of two different incidences of this bug. After the first pic was taken, I completely deleted the Knight.Run method and the event that called it, and then recreated them exactly, before saving (as the version which has been attached), closing Alice, reopening it and then making the error happen for the second screenshot. So the two bug reports are similar, but the second one is slightly more relevant to the attached world.

ErrorScreenshots.zip