> system("rundll32 url.dll,FileProtocolHandler http://www.subimo.com")
>  print $?
>  print "\n"
>  system("rundll32 url.dll,FileProtocolHandler 
> http://www2.subimo.com/start?userid=acc")
>  print $?
>  print "\n"

Not sure if this will help, but you might try replacing the system call as
mentioned here:
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/10006

Chris