Image upload not working.

I’ve done a good search through previous posts and not got anywhere.

My blog is hosted on Yahoo. I’ve got a top level dir called images and a folder in my WordPress dir called uploaded-images. I’ve made both of them 775 permissions (though i’ve tried 777 as well).

I’ve tried turning the ‘sort by month and year’ on and off in options/misc.

Whatever i try i still get “Failed to write file to disk.” when i try to upload.

I’ve looked at my index.php (in the top level of my site) and it contains only 3 lines
define(‘WP_USE_THEMES’, true);
define(‘WP_IN_ROOTDIR’, true);
require(‘.//wp/wp-blog-header.php’);

Is there anything else i should need to edit in order to use the upload functionality?