Subversion 1.6 no longer accepts carriage returns (^M) in the values of its own properties (i.e. svn:log, svn:ignore and others). Prior to 1.6 such properties were accepted. svnsync 1.6 fails when the source repository violates eol-purity on any of the relevant properties. A great many such repositories exist in the wild because Subclipse was -- until very recently -- sloppy with line endings when running on Windows. This defect is only about fixing svnsync's newfound inability to sync foreign repositories with this particular problem. The linked thread(s) also present a solution for filtering the error out of a dump file, allowing an admin to fix their own repositories. Also mentioned is that a fix has been implemented in Subclipse since this issue was raised on the lists.
Original issue reported by bpsm