Problem with logOut

[hiepsi@]

I have fixed white page, and now I only 2 problems:

1) when I logout I get error (I think, hash md5,hashlogout,.... have problem), for every time refresh page, I get another error
2) Image verify when user register not show correct

I used windows server not UNIX
You can try login at: http://buonchuyen.vn/forum

user: check111
pass: 123456

After Logout this user you get error bellow, or some thing other error same

Images bellow

[Marco van Herwaarden]

To troubleshoot this, please remove any hacks and disable your plugins, then see if you still have this problem.
Note: To temporarily disable the plugin system, edit config.php and add this line right under <?php

define('DISABLE_HOOKS', true);

If so, reupload all the original vB non-image files (except install.php). Make sure you upload these in ASCII format and overwrite the ones on the server.

If your problem still exists, please create a new Style with no Parent set. Now browse the forum using this new style, do you still have the same problems? If you are troubleshooting login or guest issues, you will need to set this style as board default in the vBulletin Options.