If you are using WebDAV with WordPress then most likely the WordPress .htaccess file will break the WebDAV configuration. One basic work around for this is to turn off the Apache Rewrite Engine for the directories that you want to enable WebDAV for.
# cd into a directory within your html root where you want to enable WebDAV
$ cd /var/www/path/source
# then create a .htaccess file and disable the Rewrite Engine
$ vim .htaccess
# paste this into the vim file:
<IfModule mod_rewrite.c> RewriteEngine Off </IfModule>
Then follow the same steps for any other directories you would like to enable.