My Friend bought a Line 6 uber metal recently, the same as mine, but ive been using mine for 7 mnths and its still kick ass, but his got spoilt after 3 weeks. When he uses it for 30 mins the green light turns red and the thing shuts off! Any suggestions on what could be wrong?
It could be a simple fault with the power cable, it depends if hes using an old power feed or a new one, be it new then I suggest you take it back to where he bought it.

Also though i've been using line 6 stuff alot, and it is very peticular with what you use, so much so it will "faulter" if you dont use ALL line 6 stuff, even down to the cables...so I suggest that too, if its within 3 weeks then im sure the store isn't gonna say much, unless you've just toured europe on the pedal (which i doubt).

But the fact it works then doesn't kinda points to faulty cables and/or power feed.
Filth, pure filth... That's what you are.
Use an adaptor, or take it back if it's the actual pedal that's faulty.

Tell him not to leave the cables in the pedal when not playing, it has the same affect as having it on, really, really draining the battery quickly.
"Breathe, breathe in the air
Don't be afraid to care"

Fender Strat/Tokai LS80>few pedals>Orange Rocker 30