in reply to
What is the difference between Windows fork an Unix fork ?
fork() on Windows does not exist. It is emulated through a variety of options, depending on whether you're using the native ("MSWin32") Perl compiled with MSVC, or the Cygwin Perl. fork() on Cygwin likely works I guess, and on MSWin32, it works for those who implemented it, but I can only recommend to stay away from it and use other mechanisms of launching programs, like system(1,...) or system("start $command"); or Win32::Process.