[Threepwud]

I am trying to change ' to an apostrophe ' but it makes my page display a database error:

Database error in vBulletin 4.0.6:
Invalid SQL:
UPDATE thppost
SET pagetext = replace(pagetext, 'I'', ''');
MySQL 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 '''')' at line 2
Error Number : 1064
Request Date : Saturday, September 11th 2010 @ 12:34:43 PM
Error Date : Saturday, September 11th 2010 @ 12:34:43 PM
Script : http://www.threepwud.com/vb/showthre...ndings?p=46049
Referrer : http://www.threepwud.com/vb/forum.php
IP Address : 94.170.240.143
Username : Threepwud
Classname : vB_Database
MySQL Version : 5.1.41

Any ideas?
Thanks mate