Mac Forums

I did a little re search and found lots of people were having problems but i found none like mine. Whenever i open itunes nothing comes up telling me about an update and when I press "check for update" it says the current version is 4.2.1! I've already tried restoring my ipod and just downloading the ios update and updating it myself but when i do that it says "the ipod could not be updated because the firmware file is not compatible". I already have my itunes up to date (10.5) and i have no clue what could be wrong. help!