1. I am not able to find any distribution failed messages, but able to see one download failure message on 12-9-12. It may be due to various reasons like internet was not available at the particular time. You may have to look into other logs as well for information.
2. The first message is related to the purge of old contents. This is configurable under configure-->Preferences in LUA
The second message says there is no content to purge as per the configuration under configure-->preference
The third and fourth about the content distribution schedule which can be configured under download and distribute tab in LUA.( Clients will be downloading updates from this distribution point.)