If an error occurs, and we are running from the client sapi api, just display the raw error on a new line and do not attempt to add any html formatting
limit_email_domains: Allow users to be locked to a choice of multiple email domains, instead of a single domain. For example:

 $g_limit_email_domains		= array( 'users.sourceforge.net', 'sourceforge.net' );

would allow people to sign up using email address @users.sourceforge.net or @sourceforge.net only
1) Always treat debug email address as a string (this makes phpdoc/clients that try to do type checking less confused)

2) Use PHP's own email validation routines (available since php 5.2)