My custom form tries to send an Email and access FreeBusy time of some
resources and these security prompts are very annoying. I know that Sue
explained this issue in the book and on the web site. But there are some
more questions that I have regarding this issue:
1. Why only users with Outlook 2000 SP3 got these prompts, but there are no
prompts for Outlook 2003 with any SP?
2. in 13.5.3 paragraph of your book, Sue, you stated that "You can set the
"To" properties on a message without triggering security prompts. How?
3. If we have a mixed environment with Outlook 2000 and 2003, which
Administrative security components have to be installed on our Exchange 2000
server to "fix security prompts".

1. Why only users with Outlook 2000 SP3 got these prompts, but there are no
prompts for Outlook 2003 with any SP?

Because Outlook 2000 can run on operating systems that are inherently insecure. Outlook 2003 requires a more secure, recent o/s and so can afford to allow VBA, Outlook form code, and add-ins to run without prompts.

2. in 13.5.3 paragraph of your book, Sue, you stated that "You can set the
"To" properties on a message without triggering security prompts. How?

Item.To = ; "

3. If we have a mixed environment with Outlook 2000 and 2003, which
Administrative security components have to be installed on our Exchange 2000
server to "fix security prompts".

See http://www.slipstick.com/outlook/esecup/admin.htm
--
Sue Mosher, Outlook MVP