The servers have officially been closed, so that pretty much guarantees this achievement will never be fixed.Marvel Heroes Omega Has Shut Down
Also, I want to thank Serious X Devil for pointing out that the servers had closed. Also, congratulations to anyone who got this achievement before the DLC broke it.
The object was to unlock every achievement in the base game. However, this achievement broke when the DLC achievements came out and is now unobtainable. Sadly, since the developer is dropping support for the game, it may never be fixed.