I'm making some changes to adapt the IceTorque map to vanilla 1.5 and I'm getting the following error:

Couldn't find 'parthia' in descr_regions.text line 437 row 45...and then says not found in 'string table'.
My question is, what is the string table? I've looked thru every related file I can find or think of, and they all say what they are supposed to say, and parthia is a playable faction. Could someone offer a hand? Thanks.