If for some reason posterIP is empty, skip it when doing trackUser

Sources/ManageMembers.php

@@ -1938,7 +1938,7 @@ function trackUser($memID)
 	$request = db_query("
 		SELECT posterIP
 		FROM {$db_prefix}messages
-		WHERE ID_MEMBER = $memID
+		WHERE ID_MEMBER = $memID AND posterIP<>''
 		GROUP BY posterIP", __FILE__, __LINE__);
 	$context['ips'] = array();
 	while ($row = mysql_fetch_assoc($request))
@@ -2385,4 +2385,4 @@ function reattributePosts($memID, $email = false, $post_count = false)
 	return db_affected_rows();
 }
 
-?>
+?>