IPOD APP PROBLEM!!!!!?

Okay so im trying to download apps for my ipod touch; As its downloading when its done a box pops up saying "There was a problem downloading "APP NAME HERE" "The file seems to be corrupted. To re-download the file choose "Check for available downloads" from the store menu." When i do that it tries to download it again. And the box keeps reappearing. What am i doing wrong. The app just wont download; HELP ME PLEASE!!!