File Permissions – Denied

Hi,

So I’ve taken over a site from the original designer/developer.
I grab a php file and make amendments on my computer. When I upload the file to the server I’m getting a permission denied message for file and folder (plugin) uploads.

I’ve tried to manually change the file permissions on the server, following the instructions on this page…
http://codex.wordpress.org/Changing_File_Permissions

I’ve even tried to change the numeric value to 777 on various files. Still no luck. Is there a chance file permissions could be held by the host?

I’ve also tried to amend the .htaccess file but there is nothing related to permissions that exists in the file to amend (for the site I’m working on).