Unable to export

[NTLDR]

Sound odd, give this a shot in an SSH window:

mysqldump --opt -uUSERNAME -p DB_NAME > backup.sql

Replace USERNAME (note the lack of space after the -u) with the username you have entered in your vB config.php and do the same for DB_NAME with your database name, when it asks for a password enter the one thats in config.php.

Is the servername in config.php localhost? If not thats probably why it doesn't work.