Shayne O'Connor wrote: > TypeError: unsupported operand type(s) for +: 'NoneType' and 'str': > File "SConstruct", line 674: > have_cxx = conf.TryAction (Action (env['CXX'] + ' --version')) > flowbot at machine:~/dev/svn/copy of ardour2$ So there was no CXX environment variable. Have you got a C++ compiler installed?