IMHO, if you want to execute a .net program on windows, you should use someting like this:

    my $CmdNgen          = "$fw20cmd\\ngen.exe";
    my $ParmNgenPause    = "ngen queue pause";
    my $rc;
    $rc = ProcessItWin( $CmdNgen, $ParmNgenPause );

    sub ProcessItWin {

        my ( $ProcessCmd, $ProcessParam ) = @_;
        my $ProcessObj = undef;

        #print "Start $ProcessCmd $ProcessParam\n";

        my $rc = Win32::Process::Create( $ProcessObj, $ProcessCmd, $Pr
+ocessParam, 0, NORMAL_PRIORITY_CLASS, q{.} )
            or $rc = ErrorReport($ProcessCmd);

        my $pid = $ProcessObj->GetProcessID();

        $ProcessObj->Wait(INFINITE);

        return $rc;

    }

    sub ErrorReport {
        my $cmd = shift;
        print "\n *** Error CreateProcess: Command=$cmd, ", Win32::For
+matMessage( Win32::GetLastError() ), "\n";
        return 0;
    }
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Also please read perldoc Win32::Process