iCal reminder opens mail every time :/

I dont use Apple Mail. I use Gmail and the Gmail Dock app. I have a my google calander setup i iCal.

But every time I get a reminder for an appointment it opens Mail and promts me to enter account data. Can I disable this somehow???

When you create the event in iCal and set up an email alert, you will get a drop down of the email account you want the alert to go to. That's where you would select your gmail. You've never set up your Gmail in the Mail app?? For some reason, that's where iCal is trying to send it.