Threadmin_admin is NOT a stand-alone product.  It can only be used if you have already installed threadmin: http://www.vbulletin.org/forum/showthread.php?t=117483

This add-on will provide a central place where you can view and delete thread permissions that were granted via threadmin.

INSTALLATION:

1. Upload the files located in the upload folder
2. Via the admincp -> Manage Products, import product-threadmin_admin.xml
3. Set usergroup permissions.

Done!