Database transfer failure

[greeniche]

I installed 1.4.9 in a folder under the public-html of the root as I failed to do the upgrade to 1.5.3 (which gave me a mess in the backoffice) so I rollback (luckily no problem).

 

Then I installed 1.5.2 through my web hosting company cpanel in another folder also under public-html. I tried to import the old database file which ended in ".sql.bz2" created under Backup in Tools by the following instructions stated in Backup.

 

How to restore a database Backup in 10 easy steps:

• Set "Enable Shop" to "No" in the "Maintenance" page under the "Preferences" menu.
  
• Download the Backup from the list below or from your FTP server (in the folder "admin/backups").
  
• Check the Backup integrity: look for errors, incomplete file, etc. Be sure to verify all your data.
  
• Ask your hosting provider for "phpMyAdmin" access to your database
  
• Connect to "phpMyAdmin" and select your current database
  
• Unless you enabled the "Drop existing tables" option, you must delete all tables from your current database.
  
• At the top of the screen select the "Import" tab
  
• Click on the "Browse..." button and select the Backup file from your hard drive
  
• Check the max. allowed filesize (e.g. Max: 16MB)
  If your Backup file exceeds this limit, contact your hosting provider
  
• Click on the "Go" button and wait during the import, the process can take several minutes
  

However, when I tried to import, it said the file has to be ended either gzip or zip so my .sql.bz2 doesn't work.

 

Is there any way that I can change the extension or I could not import database across different versions installed in different folders by this way?

 

Thank you in advance for any advice.