MySQL server has gone away - production site
Culprit may be max_allowed_packet which is too little. Drupal Requirements page suggests 16M, but it depends on your site. If you are not able to get sufficient memory allocated, better change host.


  When using Drupal 5.x or later, particularly with contributed modules,
  it may be necessary to set the system variable max_allowed_packet to
  at least 16M. Some inexpensive hosting plans set this value too low
  (the MySQL default is only 1M). In that case, you may need to choose a
  better hosting plan. A value of 1M may be sufficient for 5.x.