Sorry, no, those errors have nothing to do with your map loading problem, they are due to some art that the client looks for, but doesn't exist yet (or was removed, I haven't looked into it much). I have heard of other players crashing after changing to the grassless maps, but I haven't heard of anyone that pinpointed why... I personally used grassless maps I made myself, so I downloaded the ones linked from the main site, and they worked fine for me on svn, I don't have a release binary to test.
So I don't know, has anybody else managed to identify this problem?
By the way, you did back up the original maps right?
