diff --git a/change_log.txt b/change_log.txt
index 0714689e..f43245f9 100644
--- a/change_log.txt
+++ b/change_log.txt
@@ -1,4 +1,7 @@
 ===== trunk  =====
+29.11.2011
+- bugfix added exception if the default plugin handler did return a not static callback (Forum Topic 20512)
+
 25.11.2011
 - bugfix {html_select_date} and {html_slecet_time} did not default to current time if "time" was not specified 
   since r4432 (issue 60)
diff --git a/libs/sysplugins/smarty_internal_templatecompilerbase.php b/libs/sysplugins/smarty_internal_templatecompilerbase.php
index 0f218384..1f50be75 100644
--- a/libs/sysplugins/smarty_internal_templatecompilerbase.php
+++ b/libs/sysplugins/smarty_internal_templatecompilerbase.php
@@ -521,14 +521,17 @@ abstract class Smarty_Internal_TemplateCompilerBase {
                     }
                     include_once $script;
                 }  else {
-                    throw new SmartyCompilerException("Plugin or modifer script file $script not found");
+                    $this->trigger_template_error("Default plugin handler: Returned script file \"{$script}\" for \"{$tag}\" not found");
                 }
             }
+            if (!is_string($callback) && !(is_array($callback) && is_string($callback[0]) && is_string($callback[1]))) {
+                $this->trigger_template_error("Default plugin handler: Returned callback for \"{$tag}\" must be a static function name or array of class and function name");
+            }
             if (is_callable($callback)) {
                 $this->default_handler_plugins[$plugin_type][$tag] = array($callback, true, array());
                 return true;
             } else {
-                throw new SmartyCompilerException("Function for plugin or modifier $tag not callable");
+                $this->trigger_template_error("Default plugin handler: Returned callback for \"{$tag}\" not callable");
             }
         }
         return false;