Index: trunk/kernel/include/category.php
===================================================================
diff -u -N -r3174 -r3179
--- trunk/kernel/include/category.php	(.../category.php)	(revision 3174)
+++ trunk/kernel/include/category.php	(.../category.php)	(revision 3179)
@@ -40,7 +40,10 @@
      
      function StripDisallowed($string)
      {
-     	$not_allowed = Array(' ', '\\', '/', ':', '*', '?', '"', '<', '>', '|');
+     	$not_allowed = Array(	' ', '\\', '/', ':', '*', '?', '"', '<', '>', '|',
+     							'~', '!', '@', '#', '$', '%', '^', '&', '(', ')', 
+     							'+', '=', '-', '{', '}', ']', '[', "'", ';', '.', ',');
+     							
      	$string = str_replace($not_allowed, '_', $string);
      	$string = preg_replace('/(_+)/', '_', $string);