by Ken Task.
Think investigating why one lost connection to the MySQL DB host is key here. Continuing to do the same thing with automated backups will (if the above isn't resolved) render same results. and, since automated backups won't give you errors you can find ... easily ... we'll be no further down the road to resolution (the report for automated backups really doesn't give much info when they fail).
You might need to refer to actual server logs - apache/mysql/php.
'spirit of sharing', Ken