Uninvited guests

Do nice hackers exist? Apparently so. One such hacker left a file on my web server with the following message:

"Birgun Herkes Beyaz Kefen Giydiginde Siyahin Degerini Anlayacaksiniz // CeNGiZ-HaN WaS HeRe FoR SGB-TeaM"
How did he get in? What does the message mean? I don't know! I am just grateful he didn't do any real damage!