Updated the get_module_db call fixing a rare condition

Author: detain

src/modules.php

@@ -142,7 +142,13 @@ function get_module_db($module)
             if ($module != '' && $module != 'default') {
                 myadmin_log('myadmin', 'info', "Tried to get_module_db({$module}) and GLOBALS[{$module}_dbh] does not exist, falling back to GLOBALS['tf']->db", __LINE__, __FILE__, $module);
             }
-            return clone $GLOBALS['tf']->db;
+            global $default_dbh, $tf;
+            if (is_object($tf) && method_exists($tf, 'db')) {
+                return clone $tf->db;
+            } else {
+                return clone $default_dbh;
+            }
+            
         }
     }
 }