seeing this failure regularly in my cron scripts, seems to always be the same server:

msync.CentOS.org rsync service (centosr4)
---------------------------------------

This service is intended for the sole use of the CentOS worldwide mirror network
to synchronize mirrors.

Unless you are running or intending to run a listed public CentOS mirror
use a mirror listed at http://www.CentOS.org/modules/tinycontent/index.php?id=13

If you intend to populate a mirror for public use please read the
notes at :- http://www.CentOS.org/modules/tinycontent/index.php?id=15

If you do use this service then it is implied that you are providing a
mirror for public use and giving us authority to publicise such mirror.

@ERROR: failed to open lock file
rsync error: error starting client-server protocol (code 5) at main.c(1524) [Receiver=3.0.7]
Mirror Ended at: Tue Jan 29 08:30:01 GMT 2013