gpxuser Can't change file premissions into his game directory listing by default #4

Set permissions of '/xx.xxx.xx:xxxx/resources/default/server/xxxxx.xx' to '775'
Command: SITE CHMOD 775 xxxxx.xx
Response: 550 Could not change perms on xxxxx.xx

This way user that connects via FTP can't do anything without admin assistance. Any way to fix this? Using Ubnutu 14 x32