Hiera failures with puppet 3 rc3

I just installed puppet 3 (3.0.0-0.1rc3puppetlabs1) on a 32bit Ubuntu 12.04 'server' VM. I used the packages for the install.

I then copied over my existing modules and manifests from my production 2.7.x puppet master, and also my hiera.yaml and hieradata/*.

When I run puppet agent --test I get the following:

Error: Puppet::Parser::AST::Resource failed with error NoMethodError: undefined method `empty_answer' for Hiera::Backend:Module at /etc/puppet/environments/test/manifests/nodes/puppet_nodes.pp:47 on node ll-puppet-master-vm

The line in question is:

  class { 'basenode':
    is_puppet_master => true;
  }

Basenode is:

class basenode (
  $is_puppet_master = false,
  $apt_host = 'repo.domain.com'
  ) {
...
}

For the module, hiera is not explicitly used.

Also,

root@ll-puppet-master-vm:/usr/lib/ruby/1.8/puppet/parser/functions# ls hiera*
hiera_array.rb  hiera_hash.rb  hiera_include.rb  hiera.rb

I am either missing a dependency or config file, but I cannot figure out what at this point.

My hiera.yaml is:

---
:hierarchy:
#  - %{node_id}
  - common
:backends:
  - yaml
  - puppet
:yaml:
  :datadir: '/etc/puppet/hieradata'

My puppet.conf:

[main]
logdir=/var/log/puppet
vardir=/var/lib/puppet
ssldir=/var/lib/puppet/ssl
rundir=/var/run/puppet
factpath=$vardir/lib/facter
templatedir=$confdir/templates
report=true
server=ll-puppet-master-vm
certname=ll-puppet-master-vm
pluginsync=true
archive_files = true
listen=true

[agent]
environment=test

[master]
facts_terminus = yaml
environment=test
manifest=/etc/puppet/environments/test/manifests/site.pp
modulepath=/etc/puppet/environments/test/modules:/etc/puppet/modules
ssl_client_header=SSL_CLIENT_S_DN
ssl_client_verify_header=SSL_CLIENT_VERIFY
storeconfig=true
dbadapter=mysql
dbuser = XXXXX
dbpassword = XXXXX
dbconnections = 75
reports = store