Why does my itunes immediately crash when i open it?

I have an iMac and everytime I open iTunes an error reads the following:

"iTunes quite unexpectedly.

Click Reopen to open the application again. This report will be sent to Apple automatically."

So I click "Reopen" and it's just a continuing cycle. I've checked and everything on my computer (software, apps, etc) are updated. I even restarted just for good measure. Any ideas what is wrong and/or fixes??