I first tested this great script without the backing up of the databse selected. - all ok. When I selected to backup the databse, I get an error as follows:

Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in /var/virtual/web/..etc../..etc../idut/backup.php on line 616

Can you suggest what a solution can be?  I can back up with php admin but it's better for it all to be together - rather than 2 processes.

I'm running php 4.4.9 on a shared server.