Uhh, I love it when you guys gets all rrrrroughhh and nasty ...
*pulls up silk stockings
Sprites get black if you disable blending, so if you have any custom lines of code doing that, it might be the cause.
Now, you can of course disable blending, but as OpenGL is a huge state machine, things like this happens if you mess up the states. Where that happens in your code, is anybody's guess.
On another note.
Disabling blending on anything newer than a 3GS (and mid 90's toasters), is close to irrelevant. Due to how modern mobile hardware works, there is no longer any significant performance penalty from using blending. So if you are doing it when rendering opaque backdrops (or similar), simply dont bother.
Finally you can also disable blending "the official way", but I am not at a cocos-box right now, and I can't remember how. It might be in a private class.
*What a clever thing to put half the stuff of an open source API in private classes