apache2 with mod_dav_svn and "SVNAutoversioning on" crashes of create directory

[Netix]

I've been using apache2+mod_dav_svn with "SVNAutoversioning on" before on older Ubuntu servers with Subversion 1.4.6 without problems.

Now i've installed Ubuntu 12.04 and when i try to create a directory with my webdav client (Mac OSX Finder) i get a permission denied message - but the directory is created anyway.

I've located the problem to the MKCOL (create directory) command. If i telnet to apache on port 80 and send the command MKCOL /mynewdirectory HTTP/1.1\nHost: myexample.com the connection closes and i can see in the apache error_log that the apache child process dies.

==> /var/log/apache2/error.log <==
apache2: /build/buildd/subversion-1.6.17dfsg/subversion/libsvn_subr/path.c:368: svn_path_dirname: Assertion `svn_path_is_canonical(path, pool)' failed.
[Tue Sep 11 20:11:13 2012] [notice] child pid 8655 exit signal Aborted (6)

==> /var/log/apache2/access.log <==
[13/Sep/2012:20:21:05 +0000] "MKCOL /untitled%20folder HTTP/1.1" 405 1560 "-" "WebDAVFS/1.8.3 (01838000) Darwin/10.8.0 (i386)"

Mac OSX Finder error message:
The operation can’t be completed because you don’t have the necessary permission.

lsb_release -rd
Description: Ubuntu 12.04.1 LTS
Release: 12.04

subversion:
  Installed: 1.6.17dfsg-3ubuntu3
  Candidate: 1.6.17dfsg-3ubuntu3
  Version table:
 *** 1.6.17dfsg-3ubuntu3 0
        500 http://archive.ubuntu.com/ubuntu/ precise/main amd64 Packages
        100 /var/lib/dpkg/status

libapache2-svn:
  Installed: 1.6.17dfsg-3ubuntu3
  Candidate: 1.6.17dfsg-3ubuntu3
  Version table:
 *** 1.6.17dfsg-3ubuntu3 0
        500 http://archive.ubuntu.com/ubuntu/ precise/universe amd64 Packages
        100 /var/lib/dpkg/status

Also tested on Ubuntu Quantal 12.10 and Subversion 1.7.5-1ubuntu1:

==> /var/log/apache2/error.log <==
apache2: /build/buildd/subversion-1.7.5/subversion/libsvn_subr/dirent_uri.c:2501: svn_fspath__dirname: Assertion `svn_fspath__is_canonical(fspath)' failed.
[Thu Sep 13 20:21:05 2012] [notice] child pid 32062 exit signal Aborted (6)