I don't understand this? Mine works. My cart is pretty heavily modded but I can't see that being the problem??? (or cure) I have uploaded my version you can try it here:
http://www.goldmisers.com/Smarty2.6.2Upgrade.zip
KEEP IN MIND THAT THIS IS FOR XCART 3.5.7
Also, when you enter "Webmaster Mode":
http://www.goldmisers.com/edit.jpg