Send To mail recipient does not work

Help,
I have a client that uses outlook 98, and ie5, when he selects FILE,SEND,PAGE BY EMAIL, he gets an error “The operation failed due to network or other communication problems. Check your connections and try again.” He is hooked to a exchange server directly through a lan. I reinstalled outlook and IE to no avail, he can get and send e-mail normally, all other lan users can use this function NO PROBLEM. The “SEND TO” mail recipients, left click also generates the same error, making me believe that the problem is in outlook. Please help.

Thanks
Tom