I was practicing with my band, and as usual we were running through everything kinda calm to get warmed up to go all out, and it sounded fine, i was at a part where me and teh lead guitarist play a harmony and my riff sounded off, about half a step off, and i was confused, i finished the song with the adjustment, but it still messed with we for another full song, even thoguh i retuned it, and i dunno, it just sounded off. My friend suggested the strings were too old, so i'm restringing them, and suggestions if i'm wrong?
Did you guys tune to each other, use different tuners, or the same tuner?

It could be that one of your guitars needs to be intonated.
well,my guitar ios actually pretty well intonated, i play a Jay Turser JT-200V, and he plays an epiphone lp-100 i think, and mine has never had an issue before last night. His sounding, well, i won't say good, but like it should have, i'm not really in a position to get it adjsuted, as our bands biggest career concert is tomorrow night, and i need it fixed by then, its why i'm so worried about it, its basically gonna prove if we deserve to get signed or not
^Take your guits to a tech and have him set both of them up. Maybe lube the nut or change the tuning pegs.

You need to have them intonated together, or they'll sound a few cents off.
My only other idea is that your harmony writing was off. Have you ever played the song where it did sound ok? You may wanna make sure that your intervals are right.
Also to make sure it's you, you may wanna try inputting his part into something like guitar-pro and play along with the computer and see if it's still off to make sure it's you who needs to be jumping through hoops.
i am pretty sure your harmony was off. try posting both parts(dont worry we wont steal it) and we will see if your doing it right
well it wasn't anything new, we've played the song over 100 times, we've played it live every show, it was fine, and i would post the parts but i have no clue wtf he plays, its not hard, its just very jumpy, its a rhythm under lead kinda thing