hi, amember team http://www.vbulletin.com/forum/entry.php?2405-vBulletin-4.0.2-Maintenance-Release-Now-Available! now , vBulltein updated to 4.02 but i'm not sure vb4.01 plugins support 4.02 also or already created for 4.02 plugins. thanks note
Contact the Help Desk. They do have plug-ins for each v-Bulletin versions. They'll be happy to provide correct plug-in to you (if you already pay for it).