This is a common problem with alot of guitars, I take it that this just isn't a problem with the 1st string only and the fretting out gets worse the higher you go past the 12th fret? Assuming you don't have high fret, which you detect easily just by playing up the neck until the buzzing stopped, here's a few tips that might help, first don't adjust the truss rod, the truss rod has almost no effect on the action at the 12th fret and no effect at all past the 15th fret, don't be afraid to raise the action a little bit, it might not take much and really tremlo's need the clearence to play clean, if your Ibanez is a bolt-on neck (it is, isn't it) most bolt on necks typically have too much of a down hill angle from the body to the headstock, an easy fix is to put a small shim in between the neck and the body, an old fashioned razor blade works good, take 2 sets of pliers and break off a piece, be careful and protect your eyes, loosen your strings really slack, loosen the neck screws, slide the shim in between the body and neck, stopping short of the firstset of screws, tighten everything back up and try it out, you may have to try it afew times with shims of different thicknesses, when you get it right you can tweak your string height back down, good luck