This seems to be from only the DynRPG version. It appears to happen in the game randomly. I can only suggest taking DynRPG saves to regular version and bringing them back once you pass the error. There is no difference in event scripting between regular version and DynRPG, but DynRPG has this problem.

EDIT: It appears that the error will happen on regular version too if you transfer save. A player who has come across this error says:
“The save might be corrupted. You may have missed a trigger for an event earlier on, and the game never corrected itself. I only had that error when I didn’t have the basic RPG Maker 2003 resources in the same folder as the game.”