"Send To" Access Denied

We are running Notes 6-5-4 on a Windows 2000/Citrix FR3 server. When users try to “Send To” from MS Office, they get an error window “Lotus Notes Mailman Error”, with “Access Denied” as the message. In a separate application, the Send To produces the error “Error Initializing Notes: Access Violation at Address 60014445 in module NNotes.dll”. I scanned the forum, but couldn’t find “access denied” with the Mailman Error. Is there something in Windows, associated with Send To, that requires access rights to Lotus Notes? Any help is greatly appreciated. Thanks.