Index: branches/unlabeled/unlabeled-1.12.2/core/kernel/parser/tags.php
===================================================================
diff -u -r5718 -r5776
--- branches/unlabeled/unlabeled-1.12.2/core/kernel/parser/tags.php	(.../tags.php)	(revision 5718)
+++ branches/unlabeled/unlabeled-1.12.2/core/kernel/parser/tags.php	(.../tags.php)	(revision 5776)
@@ -313,8 +313,8 @@
 		switch ( $this->Tag ) {
 			case 'DefaultParam':
 				foreach ($this->NP as $key => $val)	{
-					$code[] = 'if (!$'.$key.') $application->Parser->SetParam(\''.$key.'\', \''.$val.'\');';
-					$code[] = '$'.$key.' = $'.$key.' ? $'.$key.' : \''.$val.'\';';
+					$code[] = 'if (!isset($'.$key.')) $application->Parser->SetParam(\''.$key.'\', \''.$val.'\');';
+					$code[] = '$'.$key.' = isset($'.$key.') ? $'.$key.' : \''.$val.'\';';
 				}
 				return $code;
 			case 'param':