Testing net-snmp gem in OS X Lion

output

/Users/bjreath/.rvm/gems/ruby-1.9.2-p290@issues/gems/ffi-1.0.9/lib/ffi/library.rb:147:in `attach_function': Function 'init_mib' not found in [libnetsnmp.dylib] (FFI::NotFoundError)
	from /Users/bjreath/.rvm/gems/ruby-1.9.2-p290@issues/gems/nice-ffi-0.4/lib/nice-ffi/library.rb:122:in `attach_function'
	from /Users/bjreath/.rvm/gems/ruby-1.9.2-p290@issues/gems/net-snmp-0.2.3/lib/net/snmp/wrapper.rb:349:in `<module:Wrapper>'
	from /Users/bjreath/.rvm/gems/ruby-1.9.2-p290@issues/gems/net-snmp-0.2.3/lib/net/snmp/wrapper.rb:3:in `<module:SNMP>'
	from /Users/bjreath/.rvm/gems/ruby-1.9.2-p290@issues/gems/net-snmp-0.2.3/lib/net/snmp/wrapper.rb:2:in `<module:Net>'
	from /Users/bjreath/.rvm/gems/ruby-1.9.2-p290@issues/gems/net-snmp-0.2.3/lib/net/snmp/wrapper.rb:1:in `<top (required)>'
	from /Users/bjreath/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
	from /Users/bjreath/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
	from /Users/bjreath/.rvm/gems/ruby-1.9.2-p290@issues/gems/net-snmp-0.2.3/lib/net-snmp.rb:7:in `block in <top (required)>'
	from /Users/bjreath/.rvm/gems/ruby-1.9.2-p290@issues/gems/net-snmp-0.2.3/lib/net-snmp.rb:6:in `each'
	from /Users/bjreath/.rvm/gems/ruby-1.9.2-p290@issues/gems/net-snmp-0.2.3/lib/net-snmp.rb:6:in `<top (required)>'
	from /Users/bjreath/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:59:in `require'
	from /Users/bjreath/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:59:in `rescue in require'
	from /Users/bjreath/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:35:in `require'
	from snmp_test.rb:2:in `<main>'

snmp_test.rb

require 'rubygems'
require 'net-snmp'

session = Net::SNMP::Session.open(:peername => "test.net-snmp.org", :community => "demopublic" )
begin
  pdu = session.get("sysDescr.0")
  puts pdu.varbinds.first.value
rescue Net::SNMP::Error => e
  puts e.message
end
session.close