Ubuntu webdav

The problem probably you face as followed.

[Sat May 19 13:20:21 2007] [notice]
Apache/2.2.3 (Ubuntu) DAV/2 PHP/5.2.1 configured 
-- resuming normal operations
[Sat May 19 13:20:53 2007] [error] [client xx.xxx.xxx.xx]
Could not DELETE /davhome/show.txt due to a failed precondition 
(e.g. locks).  [500, #0]
[Sat May 19 13:20:53 2007] [error] [client xx.xxx.xxx.xx]
The locks could not be queried for verification against a possible 
"If:" header.  [500, #0]
[Sat May 19 13:20:53 2007] [error] [client xx.xxx.xxx.xx]
Could not open the lock database.  [500, #400]
[Sat May 19 13:20:53 2007] [error] [client xx.xxx.xxx.xx]
(13)Permission denied: Could not open property database.  [500, #1]

Then..

$ sudo touch /var/lock/apache2/DAVLock
$ sudo chown www-data /var/lock/apache2/DAVLock