Try disabling your modifications/plugins and see if you still have this problem.
Note: To temporarily disable the plugin system, edit includes/config.php and add this line right under <?php
PHP Code:
define('DISABLE_HOOKS', true);
Hopefully you can not login and then delete the modification.
Questions/Problems regarding modifications/styles need to be asked in the modification/style thread. That is where the support for modification/style is - not out here in the main forums. Please note that if a modification/style is unsupported (or even if it says it is supported), you may be on your own if you chose to install it.