It looks like you have "remarked out" your configuration (see the # sign in front of $config below.
Quote: # or Configure your MAIL HOST (SMTP)
#$config{'mailhost'} =
'Multimedia file viewing and clickable links are available for registered members only!! You need to
or
!!
';
You could remove the above # sign or first try this configuration and see what happens:
# You need to assign either a mail program or
# a mail host so e-mails can be sent out.
# Configure your MAIL PROGRAM
$config{'get_mail'} = 1; # Set this from 1 to 0 if you want to use your own setting
$config{'mailprog'} = '/Your/Path/To/sendmail'; # no additional options please
# or Configure your MAIL HOST (SMTP)
#$config{'mailhost'} = 'http://YourSMTP-Host';
# Set this from 0 to 1 if the script is running with a real Web-Server
$config{'web_server'} = 1;