I get 550 when trying to delete or modify files in a folder, chmod is not possible either. For example I have a folder called templates with 6 subfolders. I am able to modify 4-5 of those but the other two failing with 550 error message. Please help me!
Which php mode have you selected in the website settings? Is suexec enabled or disabled in the website settings?
The reason for your problem is most likely that suexec was not enabled. Without suexec, files get written under the webserver and not the web user by cms systems, so that you cant change the files with FTP. To fix that, enable suexec. Then login to your server on the shell as root user and chown all files and folders inside the web directory to the webID user and clientID group of the website.