I am quite familiar with Noun じゃない and Na-adj じゃない - in both cases, they negate the noun or na-adjective, and じゃ is a colloquial form of では; ない is the plain form of ありません.
I also know that じゃ conveys the meaning of "well" or "with that" (though that's probably too formal).
せんせいじゃない ・ すきじゃない
じゃ、また。 ・ じゃ、はじめましょう。
However, what happens when じゃ is moved in front of the noun or na-adjective? For instance, in the song エアーマンが倒せない (Airman ga Taosenai / I cannot Defeat Airman) the following is heard (0:40):
I attempted the Time Barrage glitch, but against the tornado it is meaningless!
I would have written 竜巻相手に意味が無い myself.
Could it be that じゃ means に here?
Lyrics: http://www.animelyrics.com/doujin/nekokan/airman.jis (in kanji, but includes a link to romaji/ english lyrics)