Your regex isn't doing what you want. If you set $MailTo to "bob@@@tom.@blah@." then it will think that you have a fully qualified e-mail address. I would recommend that you use Email::Valid and its rfc822 method.

To figure out where your regex went wrong, check out perlre for more info.

antirice    
The first rule of Perl club is - use Perl
The ith rule of Perl club is - follow rule i - 1 for i > 1