I was getting the following error in one of my websites which seems to be a problem with open_basedir restriction enabled on the server.
Warning: file_exists() [function.file-exists]: open_basedir restriction in effect. File(/home/arunlal/public_html/wp-content/uploads/2013/08) is not within the allowed path(s): (/home/arunlal/:/tmp:/var/tmp:/usr/local/lib/php/) in /home/arunlal/domains/mydomain.com/public_html/wp-includes/functions.php on line 1337
Login as “admin” to disable open_basedir restriction in Direct Admin panel.
1. Log into Direct Admin panel as admin
2. Click on “PHP SafeMode Configuration” under Extra Features tab
3. Disable Open BaseDir for the domain.