rsync readlink failed invalid argument?

[Kendall Shaw]

I have macports 1.320. When I self port -d selfupdate it prints:

DEBUG: Rebuilding the MacPorts base system if needed.
Synchronizing from rsync://rsync.darwinports.org/dpupdate/dports
receiving file list ... done
rsync: readlink 
"/opt/local/var/db/dports/sources/rsync.rsync.darwinports.org_dpupdate_dports/aqua/MailtoMutt/work" 
failed: Invalid argument (22)
rsync: readlink 
"/opt/local/var/db/dports/sources/rsync.rsync.darwinports.org_dpupdate_dports/aqua/MenuMeters/work" 
failed: Invalid argument (22)

...

rsync error: some files could not be transferred (code 23) at 
/SourceCache/rsync/rsync-24/rsync/main.c(1161)
DEBUG: Couldn't sync dports tree: sync failed doing rsync
     while executing
"darwinports::selfupdate [array get global_options]"
Error: /opt/local/bin/port: selfupdate failed: Couldn't sync dports 
tree: sync failed doing rsync

Do you know what that means or how to make it stop failing?