Mess around with these lines in login.php
Line 51
PHP Code:
exec_header_redirect($vbulletin->options['forumhome'] . '.php');
Line 141
PHP Code:
// add consistency with previous behavior
exec_header_redirect($vbulletin->options['forumhome'] . '.php');
Line 266
PHP Code:
// no activation record, probably got back here after a successful request, back to home
exec_header_redirect($vbulletin->options['forumhome'] . '.php');