I have the same problem! I made a few changes, and ZAM, the same error message.
I, however, got it to start. I am playing the '36 campaign as the USA. Now, so far there are no real gameplay issues. All the changes come through fine. The only thing that is wrong is a bunch of "UNKNOWN STRING WANTED" messages in the game, especially in the pop up messages, lots in the tech tree (most annoying), the production screen (as they correspond to the tech tree) and almost the entire intelligence tab. Almost all the actions in the intelligence tab have the same message. They still work fine, but aesthetics suffer horribly.
Now, the strangest thing is that I only edited the stats for the provinces, and only the resources there (Oil, Steel, Pop, IC, the like). I didn't touch the tech tree. Very, very odd.
I had this edited before I patched it. The IC stayed the same, and I had the whole tech tree. But the patch eliminated the changes for the other resources. When I went back and reedited it, the same errors appeared. This says that the errors might be caused by editing the specific resources.
Also, I've done some testing myself. After this, I have (unscientifically) determined that the errors might be caused by editing only specific resources in specific provinces. When I edited the USA east coast, I had no errors. When I edited the rest of the nation, I got the error again.
Hope this helps someone determining what the hell is going on!