Database error while do backup.......

[alexchairman]

hello sir i am trying to backup my database , they showing this type of error

Database error in vBulletin 3.7.3:

Invalid SQL:
SHOW CREATE TABLE attachmentpermission;

MySQL Error   : MySQL server has gone away
Error Number  : 2006
Request Date  : Sunday, May 3rd 2009 @ 05:48:55 PM
Error Date    : Sunday, May 3rd 2009 @ 05:49:56 PM
Script        : http://xxxxxxxxxxxxxx/forums/admincp/backup.php?do=sqlfile
Referrer      : http://xxxxxxxxxxxxxxx/forums/admincp/backup.php?do=choose
IP Address    : xxx.174.xx.xx
Username      : alexchairman
Classname     : vB_Database
MySQL Version :

any solution ?