diff -ru typo3_src-4.1.7_orig/t3lib/class.t3lib_tcemain.php typo3_src-4.1.7_changed/t3lib/class.t3lib_tcemain.php
--- typo3_src-4.1.7_orig/t3lib/class.t3lib_tcemain.php	2008-06-11 12:27:08.000000000 +0400
+++ typo3_src-4.1.7_changed/t3lib/class.t3lib_tcemain.php	2008-08-19 09:06:12.000000000 +0400
@@ -1970,7 +1970,7 @@
 						$newVal = '';
 						for ($a=0;$a<$c;$a++)	{
 							$char = substr($value,$a,1);
-							if (strstr($is_in,$char))	{
+							if (strstr($is_in,$char) !== false)	{
 								$newVal.=$char;
 							}
 						}