iCal error message: reenter password. . .

I continue to experience an aggrivating message from iCal. "The password may have been entered incorrectly. Reenter the password for account “Yahoo!” on the CalDAV server “caldav.calendar.yahoo.com.” At the top of the iCal message window: "iCal can't log in on yoiur "Yahoo" account because your password may be incorrect." The account info is correct and the password as well. Ready to shoot iCal.

Thanks for any help in advance.

In Him Ruc1