Gamecube rom issues?

Hello all, just a random question/issue i seem to be having, whenever i go to download and unzip a gamecube rom its corrupt 90% of the time, not all of them are but recent ones are metroid prime 2 and a couple others whos names escape me at the moment, im not sure if its simply those games or if there is an issue overall but i wanted to post to see if anyone else had any issues