Looking at the source of Module::Starter::AddModule, it suffers from trying to use a Unixish command line approach even with the Windows default shell, which doesn't work there:

              if( $guesser->uses_module_build ) {
                        $self->verbose( "Detected Module::Build" );
                        system( $^X, 'Build.PL' );
                        system( './Build', 'manifest' );
                        }
[download]

I think a good approach here would be to make the module use the appropriate path separator for each platform.

I don't see how you can easily fix that without patching the module itself.