system("nmake") failed (RuntimeError)

I have installed rfcsdk with config --with-rfcsdk-dir="C:archiv 1\SAP\FrontEnd\SAPgui\rfcsdk"

It tells me something like :

checking for saprfc.h ... no

checking fom sapitab.h ... no

checking for main() in c.lib ... no

checking for main() in m.lib ... yes

checking for main() in dl.lib ... no

checking for main() in pthread.lib ... no

checking for main() in stdc++.lib ... no

checking for main() in rfccm.lib ... no

searching for library rfc because we cant find rfcum ..

checking for main() in rfc.lib ... no

creating Makefile

<--- ext/saprfc

<--- ext

When I execute ruby setup.rb config, it tells me something like :

setup.rb:658:in 'command' : system("nmake") failed (RuntimeError)

[

def command(*args)

$stderr.puts args.join(' ') if verbose?

system(*args) or raise RuntimeError,

"system(#{args.map{|a| a.inspect }.join(' ')}) failed"

end

]

I do not know what happens?

Thank you.