The cbb and wishcrafts Seo hack are working perfect the way they are supposed to except for the notification updates. It seems that the rewrite rule for notification_update.php is not included in the code mentioned on this wiki page https://xoops.org/modules/mediawiki/index.php/.htaccess_%26_CBB

I have added the following line to the .htaccess code

RewriteRule ^forums/notification_update.php$ modules/newbb/notification_update.php [L,NC,QSA]

and now its working. Kindly make the required changes on the wiki page if the code is correct.