When an agent is assigned to a build, the local eMake keeps in contact with the agent to make certain that the job is still running. If the agent (or the network) is very busy, it is not unusual for the handshake exchange (which is basically a heartbeat) to fail. Emake will resend the handshake message. If the agent stops responding for an extended period of time, eMake will abort the job. If the jobs are not aborting, then you can ignore such messages.