iChat help

I accidentally deleted iChat from my Dock. That iChat was from my Applications folder. So I went to "Macintosh HD, then to "Library" then to "Receipts" then I found the iChat install box logo. I was installing it, it said "an error has occurred. Reinstall again" I did that a few times. It never told me what the error was. What do I do to get my iChat to reinstall/work?

Thanks!

Dave