Sophos management agent and message router fail to load

In Sophos 9.0.11, engine 3.51.0, data 5.01

MacOS 10.9.4

I find the following failure msgs in the console log. They reappear over and over, since the process respawns and fails again. Web browsing is very slow.

7/22/14 4:03:32.157 PM %s: An exception was encountered while messaging the server: NSRangeException. Retrying: 1 attempt(s)
7/22/14 4:03:32.178 PM com.apple.launchd[1]: (com.sophos.managementagent[3627]) Exited with code: 1
7/22/14 4:03:32.178 PM com.apple.launchd[1]: (com.sophos.managementagent) Throttling respawn: Will start in 10 seconds
7/22/14 4:03:39.836 PM com.apple.launchd[1]: (com.sophos.messagerouter[3628]) Exited with code: 255
7/22/14 4:03:39.836 PM com.apple.launchd[1]: (com.sophos.messagerouter) Throttling respawn: Will start in 10 seconds

The first one looks like a broken error msg string, may not even be from Sophos. The next two clearly are.

Does anyone know what these exit error codes mean and what might be done to prevent them?

Thanks.