[99SIVTEC]

I got it to work with 3.5, but it took a couple modifications. The code that you paste in showthread should now be

if ($vbulletin->userinfo['userid'] == 0 AND !preg_match("#(googlebot|slurp@inktomi|yahoo! slurp|lycos|ask jeeves|scooter|fast-webcrawler|turntinbot|msnbot|webcrawler|Infoseek|W3C_Val|Googlebot)#si", $_SERVER['HTTP_USER_AGENT']))
{
    print_no_permission();
}

and should be done right after:

// ################################################## #####################
// ######################## START MAIN SCRIPT ############################
// ################################################## #####################