Permission problems

Hello!

I have permission problems with index.php, footer.php and sidebar.php. It tells me in the editor that I have to make this file writable before changing it.

But when I try to change permissions through FTP to “666” I get this answer “500 ‘SITE CHMOD 666 index.php’: command not understood”.

I asked the guys at the hosting to change it but they cannot do it through ch mod because they have Windows. They also say that, from what they’re seeing in Windows we should have permissions to write because the “read only” sign would be active if we didn’t. And it isn’t.

Any ideas what to do?
Is there any other way to change permissions?