iCal: "This invitation is not correct" Alert

Symptom

When you double-clicking an iCal invitation in the Mail application, an alert box with this message appears:

"This invitation is not correct. Your email address does not appear among the attendees of this event."

When you try to invite a contact to an event, an alert box with this message appears:

"Before you can invite anyone to an iCal event, you need to add their name and email address to your Mac OS X Address Book and create an address card for yourself."

Solution

One of the email addresses in an iCal invitation must correspond to one of your email addresses as noted in the Address Book application. iCal also requires that you specify your email address in the Address Book application before sending an invitation.

You can specify your card and email addresses in the Address Book application as follows:

1. Open the Address Book application.
2. Create a new contact if you are not already listed.
3. Select your name in the Address Book listing.
4. Make sure that each email address (account) you receive mail from in the Mail application is also listed in your contact information. If one or more addresses are not listed, click Edit, then click the Add (+) button next to the Email field to add additional email addresses you use.
5. Choose This Is My Card from the Card menu in Address Book.

The icon next to your name in the Address Book listing should change from a card icon to a user icon to indicate that this is your card. You should now be able to send and receive invitations.