Error with web-based mail notifications. Please HELP!!

[NickNick]

I have a form with automated mail notifications. The notifications work fine in Notes but I get the following error when saving through the web browser interface -

Error 500
HTTP Web Server: Lotus Notes Exception - Invalid document identifier

Lotus-Domino Release 5.0.6

The mailing works from an agent consisting primarily of the following formula -

@MailSend ( "OwnerEmail" ; "" ; "" ; "The following document needs your attention" ; "" ; "" ; [IncludeDoclink] )

where "OwnerEmail" is email address of the Owner. The agent is called by the "Querysave" event for Notes and by the "WebQuerySave" event for web access.

Please can somebody tell me why this is happening and what I might do to solve the problem.

Cheers

Nick