Problem with WebDAV folders in debian linux

Here is my problem:

When I try to copy some files / folders to webdav folder, I get an error in Windows XP and this log in my Linux box:

[Tue Jan 03 13:49:35 2012] [error] [client 123.123.123.123] File does not exist: /the/webdav/folder/some-file.JPG
[Tue Jan 03 13:49:35 2012] [error] [client 123.123.123.123] The locks could not be queried for verification against a possible "If:" header. [500, #0]
[Tue Jan 03 13:49:35 2012] [error] [client 123.123.123.123] Could not open the lock database. [500, #400]
[Tue Jan 03 13:49:35 2012] [error] [client 123.123.123.123] (2)No such file or directory: Could not open property database. [500, #1]