When you change Max_Allowed_Packet_Size using the command line or an admin tool, sometimes it does not work.
The best way to do this is to edit the my.cnf file. Under the mysqld section, add the following line:
Normally it is good to set the value to around 16mb. It is only set to 1mb by default.
Restart mySQL after you have edited the file:
Use services to restart