Spantini! You are a genius! That site is working on the file right now. It's been churning for a while and there's no status bar but it has to be a tricky operation.
Thanks dude, I'll post back with the results.
Edit: I tried 3 times but all I got was "Error" I asked Support what the error is most likely to be, it might be something I can fix.
Ah, I think it's not .gpx for Guitar Pro, I think it's gpx as in GPS or geographical data.