at : Pre-installation Database Restoration Site Setup Finished
"We have detected that the required maximum size for a single row SQL query is 2.81 Mb for your site. This is larger than the average site. If you receive a database error code 1153; or error message 'ER_NET_PACKET_TOO_LARGE)'; or error message 'Got a packet bigger than 'max_allowed_packet' bytes' then please ask your host to set the value of the max_allowed_packet configuration variable of your database server to at least 3 Mb. "
I wrote with my hoster and they told me that 64MB already allowed....