Works correctly for me.
Thanks Jholly, I was hoping that it was related to some permissions needing to be changed since we had just upgraded our membership but alas 24 hours later we're still getting the message.
Like I said previously, it still works when using my non upgraded membership making it all the more frustrating and suggesting that I'm not doing something stupid.
UPDATE: I've found that the LOC file works fine with Google Earth and it would be a mapsource issue? I've tried it on 2 different versions of mapsource with the same error. thoughts?