If you are getting the below error in your mysql (slave) logs:
090723 21:46:40 [Note] Slave: received end packet from server, apparent master shutdown:
090723 21:46:40 [Note] Slave I/O thread: Failed reading log event, reconnecting to retry, log 'mysql-bin.000012' at postion 106
Then, it means the slave is sharing an ID with another slave/node in the replication setup. Check the server ID to make sure it is unique.