[chef] chef-client failure on vanilla Ubuntu 11.04

hello. up until now i had been successfully running chef-clients on
CentOS against my Ubuntu chef server. now i'm trying to fire up some
ubuntu clients, and they are failing.

the failure case is constructed in the most simple way:
* i install chef-client on vanilla Ubuntu 11.04
* i run chef-client using a simple runlist: recipe[quick_start]
* it fails, yet the node is registered successfully on the server.
* the first run yields one error message, the immediate second run
  yields a different error message.

first error msg:
/usr/lib/ruby/1.8/json/common.rb:122:in `parse': undefined class/module 
Chef::CookbookVersion (ArgumentError)

second error msg:
/usr/lib/ruby/1.8/chef/node.rb:329:in `json_create': undefined method `each' 
for nil:NilClass (NoMethodError)


what to do?  i'm hoping it's something easy, something i'm overlooking,
but i can't find it.


here are the details:

the ubuntu chef-server is 0.10.8-1.


 :/etc/chef#
 uname -n
cheftestclient.dev.spergatronic.com


 :/etc/chef#
 lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 11.04
Release:        11.04
Codename:       natty


 :/etc/chef#
 chef-client -v
Chef: 0.8.16


the first chef-client run:


 :/etc/chef#
 chef-client -j j.json -l debug -L /var/log/chef/client.log -V
[snip]
[Mon, 23 Jan 2012 19:09:00 +0000] DEBUG: Saving the current state of node 
cheftestclient.dev.spergatronic.com
[Mon, 23 Jan 2012 19:09:00 +0000] DEBUG: Signing the request as 
cheftestclient.dev.spergatronic.com
[Mon, 23 Jan 2012 19:09:00 +0000] DEBUG: Sending HTTP Request via POST to 
chef.dev.spergatronic.com:443/nodes
[Mon, 23 Jan 2012 19:09:00 +0000] DEBUG: Signing the request as 
cheftestclient.dev.spergatronic.com
[Mon, 23 Jan 2012 19:09:00 +0000] DEBUG: Sending HTTP Request via GET to 
chef.dev.spergatronic.com:443/nodes/cheftestclient.dev.spergatronic.com
[Mon, 23 Jan 2012 19:09:00 +0000] DEBUG: Synchronizing cookbooks
[Mon, 23 Jan 2012 19:09:00 +0000] DEBUG: Signing the request as 
cheftestclient.dev.spergatronic.com
[Mon, 23 Jan 2012 19:09:00 +0000] DEBUG: Sending HTTP Request via GET to 
chef.dev.spergatronic.com:443/nodes/cheftestclient.dev.spergatronic.com/cookbooks
/usr/lib/ruby/1.8/json/common.rb:122:in `parse': undefined class/module 
Chef::CookbookVersion (ArgumentError)
        from /usr/lib/ruby/1.8/json/common.rb:122:in `parse'
        from /usr/lib/ruby/1.8/chef/rest.rb:202:in `api_request'
        from /usr/lib/ruby/1.8/chef/rest.rb:267:in `retriable_rest_request'
        from /usr/lib/ruby/1.8/chef/rest.rb:197:in `api_request'
        from /usr/lib/ruby/1.8/chef/rest.rb:100:in `get_rest'
        from /usr/lib/ruby/1.8/chef/client.rb:270:in `sync_cookbooks'
        from /usr/lib/ruby/1.8/chef/client.rb:86:in `run'
        from /usr/lib/ruby/1.8/chef/application/client.rb:215:in 
`run_application'
        from /usr/lib/ruby/1.8/chef/application/client.rb:207:in `loop'
        from /usr/lib/ruby/1.8/chef/application/client.rb:207:in 
`run_application'
        from /usr/lib/ruby/1.8/chef/application.rb:62:in `run'
        from /usr/bin/chef-client:25



in spite of above failure, the node was registered on the server:

[chefsrv chef-repo]$ knife node show cheftestclient.dev.spergatronic.com
Node Name:   cheftestclient.dev.spergatronic.com
Environment: _default
FQDN:        cheftestclient.dev.spergatronic.com
IP:          50.16.xx.xx
Run List:    recipe[quick_start]
Roles:
Recipes:
Platform:    ubuntu 11.04



the second run immediately after the first:


 :/etc/chef#
 chef-client -j j.json -l debug -L /var/log/chef/client.log -V
[Mon, 23 Jan 2012 19:11:59 +0000] INFO: Starting Chef Run
[Mon, 23 Jan 2012 19:12:02 +0000] DEBUG: Client key /etc/chef/client.pem is 
present - skipping registration
[Mon, 23 Jan 2012 19:12:02 +0000] DEBUG: Building node object for 
cheftestclient.dev.spergatronic.com
[Mon, 23 Jan 2012 19:12:02 +0000] DEBUG: Signing the request as 
cheftestclient.dev.spergatronic.com
[Mon, 23 Jan 2012 19:12:02 +0000] DEBUG: Sending HTTP Request via GET to 
chef.dev.spergatronic.com:443/nodes/cheftestclient.dev.spergatronic.com
/usr/lib/ruby/1.8/chef/node.rb:329:in `json_create': undefined method `each' 
for nil:NilClass (NoMethodError)
        from /usr/lib/ruby/1.8/json/common.rb:122:in `parse'
        from /usr/lib/ruby/1.8/json/common.rb:122:in `parse'
        from /usr/lib/ruby/1.8/chef/rest.rb:202:in `api_request'
        from /usr/lib/ruby/1.8/chef/rest.rb:267:in `retriable_rest_request'
        from /usr/lib/ruby/1.8/chef/rest.rb:197:in `api_request'
        from /usr/lib/ruby/1.8/chef/rest.rb:100:in `get_rest'
        from /usr/lib/ruby/1.8/chef/client.rb:151:in `build_node'
        from /usr/lib/ruby/1.8/chef/client.rb:84:in `run'
        from /usr/lib/ruby/1.8/chef/application/client.rb:215:in 
`run_application'
        from /usr/lib/ruby/1.8/chef/application/client.rb:207:in `loop'
        from /usr/lib/ruby/1.8/chef/application/client.rb:207:in 
`run_application'
        from /usr/lib/ruby/1.8/chef/application.rb:62:in `run'
        from /usr/bin/chef-client:25




tailing the server log, i only see:

merb : chef-server (api) : worker (port 4000) ~ Started request handling: Mon 
Jan 23 19:13:27 +0000 2012
merb : chef-server (api) : worker (port 4000) ~ Params: {"format"=>nil, 
"action"=>"show", "id"=>"cheftestclient.dev.spergatronic.com", 
"controller"=>"nodes"}
merb : chef-server (api) : worker (port 4000) ~ {:dispatch_time=>0.026753, 
:after_filters_time=>1.3e-05, :before_filters_time=>0.010166, 
:action_time=>0.026342}
merb : chef-server (api) : worker (port 4000) ~ 




 :/etc/chef#
 cat client.rb 
log_level          :info
log_location       STDOUT
ssl_verify_mode    :verify_none
node_name          "cheftestclient.dev.spergatronic.com"
chef_server_url    "https://chef.dev.spergatronic.com";
file_cache_path    "/var/cache/chef"
file_backup_path   "/var/lib/chef/backup"
pid_file           "/var/run/chef/client.pid"
cache_options({ :path => "/var/cache/chef/checksums", :skip_expires => true})
signing_ca_user    "chef"
Mixlib::Log::Formatter.show_time = true



 :/etc/chef#
 cat j.json 
{
  "run_list": [
    "recipe[quick_start]"
  ]
}


thanks,
kallen