In that case you should increase max_allowed_packet in the [mysqld] section of your database configuration file.
In my setup it is 1 GB, the default is 16 MB.
Alter it in litle steps, (begin with e.g. 64MB) until that message dissapears.
You can display the size of that variable in your database with the following query:
SHOW VARIABLES LIKE 'max_allowed_packet';
Much luck,
ernolf