First, 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. Also be sure to upload the admincp files to whichever directory you have set in your config.php file.

Next, disable all plugins.

Note: To temporarily disable the plugin system, edit config.php and add this line right under <?php

define('DISABLE_HOOKS', true);

Then if you still have this problem, create a new style and choose no parent style. This will force it to use the default templates. Finally empty your browser cache, close all browser windows then try again. Make sure you change to the new style and view your forums with it. Do you have the same problem?