SQL Error

Hello Everyone,
This error might be posted already and I am sorry to repeat it. Can any please help me with this? - I get this " MySQL server has gone away" I have pasted below the whole error. When I tried to find out about the error, they asked me to add this line - max_allowed_packet=100M. Even then its of no use, kindly help me!!

Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[HY000]: General error: 2006 MySQL server has gone away' in C:\xampp\htdocs\drupal712\includes\database\database.inc:2139 Stack trace: #0 C:\xampp\htdocs\drupal712\includes\database\database.inc(2139): PDOStatement->execute(Array) #1 C:\xampp\htdocs\drupal712\includes\database\database.inc(664): DatabaseStatementBase->execute(Array, Array) #2 C:\xampp\htdocs\drupal712\includes\database\database.inc(2318): DatabaseConnection->query('SELECT expire, ...', Array, Array) #3 C:\xampp\htdocs\drupal712\includes\lock.inc(167): db_query('SELECT expire, ...', Array) #4 C:\xampp\htdocs\drupal712\includes\lock.inc(146): lock_may_be_available('schema:runtime:...') #5 C:\xampp\htdocs\drupal712\includes\bootstrap.inc(420): lock_acquire('schema:runtime:...') #6 C:\xampp\htdocs\drupal712\includes\bootstrap.inc(442): DrupalCacheArray->set(Array) #7 [internal function]: DrupalCacheArray->__destruct() #8 {main} thrown in C:\xampp\htdocs\drupal712\includes\database\database.inc on line 2139

- Swathi