What steps will reproduce the problem?
1. var proc = new sys.io.Process("cmd.exe", ["/c", "start"]);
2. trace(proc.stderr.readAll());
What is the expected output? What do you see instead?
'"start"' is not recognized as an internal or external command, operable program or batch file.
Note the double quotes around _start_. It's just wrong to blindly quote all arguments in a command line.
See http://blogs.msdn.com/b/twistylittlepassagesallalike/archive/2011/04/23/everyone-quotes-arguments-the-wrong-way.aspx
What version of the product are you using? On what operating system?
hxcpp 3.0.1
Windows 7