Index: wp-includes/ms-functions.php
===================================================================
--- wp-includes/ms-functions.php	(revision 27076)
+++ wp-includes/ms-functions.php	(working copy)
@@ -489,7 +489,7 @@
 	if ( in_array( $user_name, $illegal_names ) == true )
 		$errors->add('user_name',  __( 'That username is not allowed.' ) );
 
-	if ( is_email_address_unsafe( $user_email ) )
+	if ( is_email_address_unsafe( $user_email ) && ! current_user_can( 'manage_network_users' ) )
 		$errors->add('user_email',  __('You cannot use that email address to signup. We are having problems with them blocking some of our email. Please use another email provider.'));
 
 	if ( strlen( $user_name ) < 4 )
@@ -506,7 +506,7 @@
 		$errors->add('user_email', __( 'Please enter a valid email address.' ) );
 
 	$limited_email_domains = get_site_option( 'limited_email_domains' );
-	if ( is_array( $limited_email_domains ) && empty( $limited_email_domains ) == false ) {
+	if ( is_array( $limited_email_domains ) && empty( $limited_email_domains ) == false && ! current_user_can( 'manage_network_users' ) ) {
 		$emaildomain = substr( $user_email, 1 + strpos( $user_email, '@' ) );
 		if ( in_array( $emaildomain, $limited_email_domains ) == false )
 			$errors->add('user_email', __('Sorry, that email address is not allowed!'));