Can not create file using php

Question

I want to create new file into

/etc/freeradius 

I try to run PHP script,but the file not created

This is my code:

include('Net/SSH2.php');
include('Net/SFTP.php');
$sftp = new Net_SFTP('localhost');
if (!$sftp->login('muhammad', 'Kaynetc0m')) {
exit('Login Failed');
}
$sftp->chdir( '/etc/freeradius' );
$sftp->put("sql.conf", $txt,NET_SFTP_RESUME);

I want to append text to sql.conf file into freeradius directory

this is the output:

 ls -l /etc/freeradius/sql.conf
-rw-r----- 1 muhammad freerad 12549 Eyl 25 15:27 /etc/freeradius/sql.conf

In other hands when I execute this code on other path and file it executed nice