Default I'm having problems backing up roms

It seems like once I loaded 4.3 roms I started having problems backing up roms. Now, It goes through the motion, as in it looks like it is backing it up. After it is backed up I go into a file manager and check out the file, as in the size. Everything looks alright, until I try to restore it. It's like it is a blank file. Rom manager used to work, not anymore. I go into recovery to back it up. I've tried to put the back ups on the ext.sd card, and on the internal memory. Nothing is working. I'm not sure what's going on. If anyone can help me with this problem please do so. Thanks. Oh, I'm running an sg3