In our environment, we rotate logs daily or whenever the servers are restarted. This can create a large number of log files. I had over 300. As soon as I started the agent, it would crash. I set the debug level to 4 and the last entry in the agent log was "In add_logfile()". After I deleted a number of old logs, the agent started. I'm not sure of exactly how many log files needed to be removed before the agent would start.