[Puppet Users] 400 permission denied error

I'm just getting started with puppet and there's something I can't get
working. I have a client/agent setup at the moment.

When running puppet agent for the first time, I get the following error:

puppet agent --test
dnsdomainname: Unknown host
Error: Could not request certificate: Error 400 on SERVER: Permission
denied - /etc/puppet/auth.conf

My auth.conf looks like this, which I believe is how it is out of the box.

# allow nodes to retrieve their own catalog (ie their configuration)
path ~ ^/catalog/([^/]+)$
method find
allow $1

# allow all nodes to access the certificates services
path /certificate_revocation_list/ca
method find
allow *

# allow all nodes to store their reports
path /report
method save
allow *

# inconditionnally allow access to all files services
# which means in practice that fileserver.conf will
# still be used
path /file
allow *

### Unauthenticated ACL, for clients for which the current master doesn't
### have a valid certificate

# allow access to the master CA
path /certificate/ca
auth no
method find
allow *

path /certificate/
auth no
method find
allow *

path /certificate_request
auth no
method find, save
allow *

# this one is not stricly necessary, but it has the merit
# to show the default policy which is deny everything else
path /
auth any

SElinux is off and all firewall ports are open. Can anyone help?