I periodically get following error:
Could not retrieve catalog from remote server: Error 400 on SERVER: Cannot find definition Class on node node002.local

Environment:

Centos 5.8 in xen vm:

Listen 3000
<VirtualHost *:3000>
RackAutoDetect Off
ServerName foreman.lan
DocumentRoot /usr/share/foreman/public
<Directory /usr/share/foreman/public>
Options None
AllowOverride AuthConfig
Order allow,deny
allow from all
</Directory>
ErrorLog /var/log/httpd/foreman_error.log
LogLevel warn
CustomLog /var/log/httpd/foreman_access.log combined
ServerSignature On
</VirtualHost>

Puppet on the other VM on nginx nginx-1.0.11 with p rubygem-passenger-3.0.11

server {
listen 8140;
passenger_enabled on;

passenger_min_instances 5;

ssl                     on;
  ssl_session_timeout     5m;
  ssl_certificate         /var/lib/puppet/ssl/certs/puppet001.lan.pem;
  ssl_certificate_key     /var/lib/puppet/ssl/private_keys/puppet001.lan.pem;
  ssl_client_certificate  /var/lib/puppet/ssl/ca/ca_crt.pem;

1. choose any ciphers
   ssl_ciphers SSLv2:-LOW:-EXPORT:RC4+RSA;

1. allow authenticated and client without certs
   ssl_verify_client optional;

1. obey to the Puppet CRL
   ssl_crl /var/lib/puppet/ssl/ca/ca_crl.pem;

client_max_body_size 5M;

client_header_buffer_size 8k;
  large_client_header_buffers 8 32k;

types {}
  default_type application/x-raw;

passenger_set_cgi_param HTTP_X_CLIENT_DN $ssl_client_s_dn;
  passenger_set_cgi_param HTTP_X_CLIENT_VERIFY $ssl_client_verify;

root /etc/puppet/rack/public;
  passenger_base_uri  /;

error_log /var/log/nginx/puppet-error_log info;
  access_log /var/log/nginx/puppet-access_log main;

}

puppet master conf:

[main] # The Puppet log directory. # The default value is '$vardir/log'.
logdir = /var/log/puppet

1. Where Puppet PID files are kept.
2. The default value is '$vardir/run'.
   rundir = /var/run/puppet

1. Where SSL certificates are kept.
2. The default value is '$confdir/ssl'.
   ssldir = $vardir/ssl

listen = true

[master] [15/1050]

ssl_client_header = HTTP_X_CLIENT_DN                                                                                                     
    ssl_client_verify_header = HTTP_X_CLIENT_VERIFY                                                                                          
    keylength = 32768

certname = puppet001.qs.mc
    reporturl = http://foreman.lan:3000/reports
    storeconfigs = true
    dbadapter = mysql
    dbuser = puppet
    dbpassword = l9erj4bdf_qIo
    dbserver = mgmt001.qs.mc

pluginsync = true
    factpath = /var/lib/puppet/facts

1. templatedir = /etc/puppet/manifests/templates
   syslogfacility = local6

   external_nodes = /etc/puppet/node.rb
   node_terminus = exec

   rrddir=/var/lib/puppet/rrd
   rrdinterval=$runinterval
   rrdgraph=true
   reports=log, foreman

[agent]
environment = staging
report = true
classfile = $vardir/classes.txt
localconfig = $vardir/localconfig
pluginsync = true
server = puppet001.qs.mc
runinterval = 600
pluginsignore = .svn

[test]
modulepath = /etc/puppet/modules/current/1.0.6
manifest = /etc/puppet/environments/test/site.pp

[dev]
modulepath = /etc/puppet/environments/dev/modules
manifest = /etc/puppet/environments/dev/site.pp

[staging]
modulepath = /etc/puppet/modules/current/1.0.6
manifest = /etc/puppet/environments/statging/site.pp

[production]
modulepath = /etc/puppet/modules/current/1.0.6
manifest = /etc/puppet/environments/production/site.pp