problem starting up itunes

I have been having some trouble with my Itunes account...I get the message "The file “Itunes Library.itl” does not appear to a valid Itunes Library file. Itunes has attempted to recover your Itunes library and renamed this file to “Itunes Library (Damaged) 8.itl”" when I start it up, and then I hit OK, as soon as I hit Ok I can open up Itunes fine but it does the "determining gapless playback thing"...I was just wondering how I can get it to work regularly without this message coming up? Thanks for any help.