It's strange that you don't get promps in other Outlook version from so called MS security in Outlook. I would suggest that you consider other ways to send emails to avoid outlook altogether.
Check http://www.sweetpotatosoftware.com/SPSBlog/SearchView.aspx?q=%22Email%20and%20VFP%22 and http://fox.wikis.com/wc.dll?Wiki~AutomatedEmai

If you insists on sending through outlook, check Re: Warning when accessing outlook Message #920049

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>I use this code to send e-mails via MS Office Outlook in my application:
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<snip>
> Endwith
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>If the machine has Outlook 2000, there is no problem.
>If the machine has Outlook 2007, there is no problem also.
>If the machine has Outlook 2003, Outlook ask for sending confimation.
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>Does anybody know how to avoid this in Outlook 2003?. I need it because my application must run in autonomous mode.