PhpBB error on uploading avatar from url

Philip

i already asked at phpbb.com, but it seem there;s no one notice my messages T_T, so i post it here too also,

my member get a error when uploading avatar,

Could not write avatar file to local storage. Please contact the board administrator with this message

DEBUG MODE

Line : 179
File : usercp_avatar.php

what should i do, i set my images/avatar to 777 already.

thanks,