I keep getting this error when trying to configure the upload directory with Apache 2.2 and PHP 5.3 on CentOS.
In php.ini:
upload_tmp_dir = /var/www/ht
If you have Mac OS X, go to the file root or the folder of your website.
Then right-hand click on it, go to get information, go to the very bottom (Sharing & Permissions), open that, change all read-only to read and write. Make sure to open padlock, go to setting icon, and choose Apply to the enclosed items...