500 site chmod 777.... 'command not understood'

I'm a total newbie and this might seem like a stupid question.

I'm up to:

On the server locate the file: /catalog/includes/dist-configure.php
Rename this file to configure.php and change the permissions to 777 (read-write-execute for all)

Next, on the server locate the file: /catalog/admin/includes/dist-configure.php
Rename this file to configure.php and change the permissions to 777 (read-write-execute for all)
I've renamed the files without trouble but cannot change the permissions.
I'm using FileZilla and when I right click on the file the box comes up with each box highlighted but not ticked and the numberic value is xxx. When I try either ticking every box or changing the numeric value to 777 I get this:

500 site chmod 777... command not understood.

am I missing something very obvious here?

if php is running as cgi then you will use 755 for the file and folder permissions,
then reset the includes/configure.php file to 444 after install

how would I find out if php is running as cgi... or do I even need to?

btw - thanks for the quick response! :D

Okay - I tried changing to 755 and I get the same message... except for the number of course

I suspect "command not understood" is a result of your hosting server disallowing you to change file permissions using FTP.

Use the FileManager tool in your hosting account's control panel instead.

https://www.zen-cart.com/tutorials/index.php?article=9