Outlook Express Error

I have a client that was using Outlook 97 stand-alone. I upgraded him to Outlook 98 and had a lot of issues. I set him up with Outlook Express 5.5 and it’s working fine. However when he tries to send a web page via OE from within Internet Explorer (Tools – Mail and News – Send Page), he gets the error “Unable to open the address book. The address book may not be installed properly.” Yet he can open the address book from within OE and send anything to anyone.

Thanks in advance.