if ($^O =~ /MSWin/){
        $log->_6("on Windows, using work dir $work_dir");

        my $t;

        for (split /;/, $ENV{PATH}){
            if (-x "$_/perl.exe"){
                $perl = "$_/perl.exe";
                last;
            }
        }
        for (split /;/, $ENV{PATH}){
            if (-e "$_/bbtester"){
                $t = "$_/bbtester";
                last;
            }
        }
        $log->_6("using command: $perl $t --fg");

        @args = ($t, '--fg');
    }

...

    my $bg;

    if ($^O =~ /MSWin/){
        $bg = Proc::Background->new($perl, @args);
    }
    else {
        $bg = Proc::Background->new(@args);
    }