Unresolved Minecraft Modding Problems

I just really don't understand how I could transer one file, and have it open in 360rev just fine, and transfer another file and it won't open at all. I'm not doing everything different, and I've modded my minecraft saves the exact same way plenty of times before. Given, minecraft is the only game I've modded, and I don't know much about it except for what I can and can't put it/what will and will not make my game crash, and, like I said, I've had no problems until this one which is completely out of the blue. On the random off chance it might work, I even had some blocks I was keeping in chests despwan, since I've added tons of things in, though I doubt that would have much to do with the whole modding process since they're in chests- not in my personal inventory which I'm trying to mod. I tryed changing the items I'm going to mod, and it still has no effect, though I doubted it would, but eh, it was worth a shot since I have no clue what else to do /shot

I'm still here, I just won't be checking back as frequently- eating dinner and watching tv with my husband.

I think I've completely run out of legitimate things to try... and sorry to spam.

HAHA!!!!!! Okay it was completely random, but I tried gathering some fresh materials- seeds, wood, dirt- and walked away from my project site until I couldn't see it. Saved, transfered, and everything loaded fine, so far. I only loaded it- haven't modded and resaved onto my xbobx yet, but so far, this problem has been solved.