code 23 error.

[Rob Bosch]

Normally rsync will provide more information in the output, not just the
error at the end of the log.  That is, during the transfer there could be a
line that says "Filename too long" or some other issue with reading the
file.  We typically see the 23 error code when either the file name is too
long or the directory specified in the backup set doesn't exist.  I'm sure
there are others.  Take a look at the full output of rsync and you should be
able to find the reason.

Rob