I'm not going to get into "use strict, -w and CGI" this time...

$path = "C:\Program Files\sambar51\cgi-bin";
should probably be written as
$path = "C:/Program Files/sambar51/cgi-bin";

open(TEST, ">>path\textNX.txt");
should be
open(TEST, ">>", "$path/textNX.txt");

print "Content-type: text/html\n\n";
can be written as
print "Content-type: text/plain\n\n";
since you only printing plain text.