Error Code -50

So, my computer has recently been giving me an error code -50 after having my computer back on for a while. i looked it up on the System Error Codes apple page: http://support.apple.com/kb/HT1618

everytime my computer starts to operate ordinarily, however, after 15 mins to 3 hours, the computer will start giving me error code -50s for everything i do (it usually starts with itunes error code -50 from listening to music).