replaced h/d on mac {o/s is 10.6.8} can't get itunes to work

cannot get itunes to work with new h/d on my ( i-mac 10.6.8) 2.16 ghz/intel core 2 dueo

when i try to open it i get this "The file “iTunes Library.itl” cannot be read because it was created by a newer version of iTunes. Would you like to download iTunes now?" when i download the app it just keeps telling me the same thing!