Sorry. That can't be turned off. That's a prompt from Outlook to avoid unwanted programs (e.g. worms or viruses) from using Outlook to blast emails.
If you're going to use Outlook, your best bet is to batch the requests so the person responding can allow the "program" to work for up to 10 minutes.
Randall J Weers
Membership Vice President
Pacific NorthWest Access Developers Group