When i go to join a multiplayer match, the loading screen comes up and the little icon is spinning around and then i get a "Failure to Change Resolution" error and i am back in windows.

??? how to fix this ???

suggestion...
as i got same mesaage as you in some other games...

try checking your monitor settings. I bought an Ilyama Prolite a while back, and it disallowed applications access to trying to change the resolution. So i had to search through my monitor settings to switch that 'feature' off.