We have a VDF 15.1 app that works fine with Win XP and Outlool 2003 send e-mails with the MAPI classes of VDF

Now we have the same app on a Windows 7 machine with Outlook 2007.
When we try to send an email, then we get the prompt to allow mail the access for 1 minute. When we click "Yes" then nothing happens and the e-mail is not sent.
Any ideas what we can do?

Best regards,
Peter Bosch