Table prefixes wont help out, I was just wondering since that could cause the problem. Reupload your backup

I did reuploaded the back up a lots of times, still got the same error..

hmmm.... if you have an sql file of your vb db you could manually insert the tables back in with an sql query.

Do you mean.. copy the session/user tables and run them in the phpmyadmin ?

well if you had a .sql file of your db it would contain all the tables and their seperate datas in sql queries, so bascially all you do is copy and paste the sql query for your user and session tables and run them in phpmyadmin's query window;)

Thanks for the help..

How did it happened? why did there is no session/user tables ... in the database? just wondering.

hmm not sure, probably since it was a backup done by cpanel while it was reuploading it skipped over it or it was never backed up in the first place or an error occured when reinserting those tables and it just continued on reuploading , not inserting those 2 tables. i would also go over to vbulletin.com and find the full list of tables your susposed to have(wana make sure your not missing any others)

Is there any other way to back up the MySQL database execpt via cpanel?

yes, via admincp in vbulletin. import & maintenance->backup database
;)

Cool, thanks!