I've been able to change things in our control panel with no problem for quite a while, but all of a sudden when I try to do most things (change language settings, posts per page, etc.) I get this error:

e:/coastnet/ubb/languages/english/addpost.php is not writeable. Please fix the permissions on this file and try again.

My I.S. department and I have gone over and over the permissions, and they look fine. I can even open up the folder in question, locate the files, and update them manually with no permission errors.

Can anybody think of any reason why this might be happening? I'm an administrator, and none of my other admins can update settings anymore either.

Thank you!