method_missing': unknown property or method `document' (WIN32OLERuntimeError)

Symptom:

while running the test case we are getting the following error.
D:/Installations/Ruby/lib/ruby/gems/1.8/gems/watir-1.5.6/./watir/ie.rb:447:in `method_missing': unknown property or method `document' (WIN32OLERuntimeError)
    HRESULT error code:0x800706ba
      The RPC server is unavailable.    from D:/Installations/Ruby/lib/ruby/gems/1.8/gems/watir-1.5.6/./watir/ie.rb:447:in `document'
        from D:/Installations/Ruby/lib/ruby/gems/1.8/gems/watir-1.5.6/./watir/locator.rb:31:in `each_element'
        from D:/Installations/Ruby/lib/ruby/gems/1.8/gems/watir-1.5.6/./watir/locator.rb:40:in `locate'
        from D:/Installations/Ruby/lib/ruby/gems/1.8/gems/watir-1.5.6/./watir/container.rb:740:in `locate_tagged_element'
        from D:/Installations/Ruby/lib/ruby/gems/1.8/gems/watir-1.5.6/./watir/link.rb:24:in `locate'
        from D:/Installations/Ruby/lib/ruby/gems/1.8/gems/watir-1.5.6/./watir/element.rb:53:in `assert_exists'
        from (eval):2:in `href'
        from D:/Installations/Ruby/Projects/Learning/Create_Company_Order_Services/order_service.rb:50
        from D:/Installations/Ruby/lib/ruby/gems/1.8/gems/watir-1.5.6/./watir/ie.rb:447:in `each_with_index'
        from D:/Installations/Ruby/Projects/Learning/Create_Company_Order_Services/order_service.rb:46:in `each'
        from D:/Installations/Ruby/Projects/Learning/Create_Company_Order_Services/order_service.rb:46:in `each_with_index'
        from D:/Installations/Ruby/Projects/Learning/Create_Company_Order_Services/order_service.rb:46
        from D:/Installations/Ruby/Projects/Learning/Create_Company_Order_Services/order_service.rb:19:in `each'
        from D:/Installations/Ruby/Projects/Learning/Create_Company_Order_Services/order_service.rb:19



Solution:
This error is usually caused by IE being closed before watir has finished with it - Im assuming that's not happening here though.