Permissions Errors even though everything’s set to 7777

Hi,
Every theme i try this on results in the same error. I try to edit the sidebar.php file and i receive this message:

Warning: fopen(/home/powerser/public_html/wp/wp-content/themes/default/sidebar.php) [function.fopen]: failed to open stream: Operation not permitted in /home/powerser/public_html/wp/wp-admin/theme-editor.php on line 60

Warning: Cannot modify header information – headers already sent by (output started at /home/powerser/public_html/wp/wp-admin/theme-editor.php:60) in /home/powerser/public_html/wp/wp-admin/theme-editor.php on line 75

At first I assumed this was a permissions error, i’ve tried every possible way. Please let me know what I’m not doing. I’ve tried to re-install too.