The problem has to be map related, but I can't interpret the coding yet, so get someone to read that to you and then you'll be able to solve the issue! It could be something as simple as bad written coding in the map editor.
I've looked at the map and tested both the SDV forum and Nexus downloads and I'm not getting that error either. I think you're going to need more info, such as where in the map it's crashing, what season and crop it is crashing on, if it happens on another save (with the same farm type), if it happens on any other map (different farm maps), etc. EDIT: Looking for this error came up with Shenandoah Acres map as well. One more thing to ask would be did they switch to your map from a different map within the same save file? The issue shouldn't be your map as far as I can tell, and might be particular to the save file.
To be more precise, it seems the game couldn't find the action it needed to do when walking into/through grown or growing crops (the slight wobbling animation it gives crops when you walk into them). If that's correct, then they won't have problems standing on simple tilled dirt with or without a seed in it, just crops that have grown / are growing and have a collision action/animation.
