zantanzuken

in both cases, the most likely suspect is a block in your world doing something its not supposed to, or a block that shouldnt exist thats locking it up... etc etc etc. normally i'd suggest using mcedit to rectify that problem, but it doesnt work for tekkit worlds as far as i know. it didnt for mine but you can try it. what you CAN try is running the world in a normal bukkit server, which will cause plenty of errors but i believe will make it either fix itself, delete all the "mod" items in the world, or at the very least make it openable in MCedit, which will allow you to find the problem a

... i had an idea. if your going to have two people dukeing it out with quantum/gem armor, and the person with gem armor has a ton of EMC anyway... why dont they use a mercural eye to trap the quantum player in redmatter blocks? if they dont have a red matter pickaxe (perhaps prefering to use the IC2 diamond drill and mining laser) then they literally cant get out, and will eventually lose all charge in their armor, suffocating to death. not only that, a giant pillar of red matter blocks would look pretty flashy to anyone watching the fight from outside.