If it's reading 14v it's severely discharged. Works out to 2.3v/cell assuming they're discharged evenly, which is a good way beyond what they should be. A high end charger might be able to resurrect it. Have you tried Charge or Storage instead of Balance? The Imax might happen to be okay with the lowlow voltage in other modes. It's very possible the pack is permanently damaged and trying to force charge into it could be dangerous, so I would put it outside and keep a very close eye if it does accept it. It might also be wildly unbalanced so only charge to say 3v per cell and then switch to balance.

Not very recommended but you might save it. Looks like overdischarge, easy enough to do but you won't do it again. :P

I'd suggest getting a LiPo alarm/voltage reader for a couple quid from Hobbyking. Allows you to stay on top of the voltage and stay above unsafe.