Hola,
De
http://dev.mysql.com/doc/mysql/en/BLOB.html :
Cita: The maximum size of a BLOB or TEXT object is determined by its type, but the largest value you actually can transmit between the client and server is determined by the amount of available memory and the size of the communications buffers. You can change the message buffer size by changing the value of the max_allowed_packet variable, but you must do so for both the server and your client program.
No se si en caso de no poder cambiar la configuracion, se podria solucionar insertar un cacho del fichero y luego en disitntos update concatenar el resto de cachos.
Saludos.