If you're under a linux server, ignore the SMTP option, it'll use the default sendmail information in the php.ini.

As for mailing on new registration; it should mail all admins when a new user registers so long as you have the registration moderation queue enabled.

I am a Web Development Contractor, I do not work for UBBCentral. I have provided free User to User Support since the beginning of these support forums.
Do you need Forum Install or Upgrade Services?
Forums: A Gardeners Forum
UBB.threads: UBBWiki, UBB Styles, UBB.Sitemaps
Longtime Supporter & Resident Post-A-Holic
VNC Web Services: Code Modifications, Upgrades, Styling, Coding Services, Disaster Recovery, and more!