Thanks for your help.
I've added the PHP codes to my PHP file but nothing changed.
After that i connected to the machine via SSH , but i could not find the location /etc/log/httpd/error_log or /etc/log/syslog and /et/log/messages
You could said /var/log/apache2/ other_vhosts_access.log ?
i saw these lines :
XXX.XXX.XXX.XX XX.XXX.XXX.XXX(My IP's) - - [20/Apr/2014:14:35:19 -0400] "GET /arduino-push/test.php?title=Test&message=Test45 HTTP/1.1" 500 190 "-" "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.17 (KHTML, like Gecko) Chrome/24.0.1312.57 Safari/537.17"