can' read mac address on w2k8r2 system

[elockhart]

When I use macaddr on a w2k8r2 system it does not find the mac address

irb(main):026:0> Mac.addr

RuntimeError: all of /sbin/ifconfig /bin/ifconfig ifconfig ipconfig /all failed
from C:/Program Files (x86)/Shoreline Communications/ShoreWare Director/Ruby/mingw32/lib/ruby/gems/1.9.1
caddr-1.4.0/lib/macaddr.rb:67:in address' from (irb):26 from C:/Program Files (x86)/Shoreline Communications/ShoreWare Director/Ruby/mingw32/lib/ruby/gems/1.9.1 ilties-3.1.1/lib/rails/commands/console.rb:45:instart'
from C:/Program Files (x86)/Shoreline Communications/ShoreWare Director/Ruby/mingw32/lib/ruby/gems/1.9.1
ilties-3.1.1/lib/rails/commands/console.rb:8:in start' from C:/Program Files (x86)/Shoreline Communications/ShoreWare Director/Ruby/mingw32/lib/ruby/gems/1.9.1 ilties-3.1.1/lib/rails/commands.rb:40:in<top (required)>'
from script/rails:6:in require' from script/rails:6:in

'
irb(main):027:0>

If i run

systemu('ipconfig /all') 

from rails console i do get output

using ruby 1.9.2.p136