Outlook 2003 sending read receipt every 1 minute

[Teresa]

I have a user that as soon as she opens her Outlook
2003 it starts sending read receipt notifications to
another individual. It is being sent every 1 minute and
we cannot figure out what causing all this.

When outlook is closed, the read receipt is no longer
sent.

I have checked for rules and possible viruses and have
disabled the read receipt tracking option with no luck.

Anybody have an idea where to look or what could cause
such a behavior ?

Thanks.