Version: Outlook 2003

I imported an medium size address book from Thunderbird via a CSV
file. Whenever I choose new message to this contact, I get the error
as listed above:

You must first enter a valid email address for this contact before
Outlook can send mail to it

I have tried top open the record in question and then save, but I
still get this error. How can I resolve this, if possible?

Thanks, Brooks