Error from a modded map

[BostonJohnny1226]

I using Cazz64's Old Timer USA 4X map. I get the following error. I've gotten the same error on a couple of other modded maps.
If someone could please tell me what it means and how to fix it, I'd appreciate it.

Error: addRequiredCropType foliage must match the size of the ground terrain detail.

[Ntone]

No solution for this?
My map, based on the same map as above, "hangs"/lags continuously, I'm guessing the error has something to do with it...