<?php
				$result = mysql_query("INSERT INTO ".UPREFIX."items` VALUES (
				'', 
				'".$item_name."', 
				'".$item_descr."', 
				'".$item_action."', 
				'".$item_rarity."', 
				'".$item_value."',
				'".$item_folder."',
				'".$item_image."',
				'".$item_cat_id."',
				'".$item_visibility."')");
?>

I didn't know if this would be php or MySQL. I'm getting returned the following error:

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ' VALUES ( '', 'Arm', 'Army!', 'Huu', '3153', ' at line 1Arm

Note the tabs and newlines, don't know if it affects the situation...

Sorry, stray accent mark

Have you tested that SQL query with a text including a single quote ?
e.g. Sean O'Connor

Thanks, I fixed it