[Marco van Herwaarden]

If you think this is an issue with standard vBulletin Paid Subscirptions, then best to open a support ticket so 1 of the support staff can have a look at your site. Based on only this description it is not possible to determine what is wrong.

But you can first try the following yourself:

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.