Admin demo not working

[jeroentest]

Your admin demo is not working :

Here is the problem :
<!-- Database error in vBulletin: Invalid SQL: SELECT username,userid FROM user WHERE userid=
mysql error: You have an error in your SQL syntax near '' at line 1
mysql error number: 1064
Date: Thursday 07th of September 2000 10:01:47 AM
Script: /admindemo/
Referer: http://www.vbulletin.com/admindemo.html
-->

Can you fix it .. i want to see before i buy ..

Thanks ,,

Jeroen