MD5 failure

Ubuntu 12.04 LTS, Ansible version 1.5 (devel 5cbe24913f).

Ansible error when copying some files to the remote machine:

warning: md5sum command failed unusually, please report this to the list so it can be fixed
command: [u’(/usr/bin/md5sum /var/www/wordpress/wordpress-3.8.1/wp-admin/admin-ajax.php 2>/dev/null)‘, u’(/sbin/md5sum -q /var/www/wordpress/wordpress-3.8.1/wp-admin/admin-ajax.php 2>/dev/null)‘, u’(/usr/bin/digest -a md5 /var/www/wordpress/wordpress-3.8.1/wp-admin/admin-ajax.php 2>/dev/null)‘, u’(/sbin/md5 -q /var/www/wordpress/wordpress-3.8.1/wp-admin/admin-ajax.php 2>/dev/null)‘, u’(/usr/bin/md5 -n /var/www/wordpress/wordpress-3.8.1/wp-admin/admin-ajax.php 2>/dev/null)‘, u’(/bin/md5 -q /var/www/wordpress/wordpress-3.8.1/wp-admin/admin-ajax.php 2>/dev/null)‘, u’(/usr/bin/csum -h MD5 /var/www/wordpress/wordpress-3.8.1/wp-admin/admin-ajax.php 2>/dev/null)']

That’s pretty weird! We do a lot (and by which I mean it’s 50% of our testing) on 12.04.

Can you check and see which is the first ones of the commands on the list that is available on your OS and what it returns if you run it manually?