Problems with setting up subversion

I have set up a repository for a client.

When giving:
    svn list svn://localhost

I get nothing. As expected, because the repository is empty.

But when I try:
    svn mkdir svn://localhost/test -m ''

I get:
    svn: Authorization failed

On my own system I can do this without a problem.

On my system subversion runs as:
    svn 2696 1 Mar22 ? 00:00:00 Ss /usr/bin/svnserve -d -r /srv/svn/repos
On the client system:
    svn 25242 1 Mar22 ? 00:00:00 Ss /usr/bin/svnserve -d --pid-file /tmp/svnserve.pid -r /srv/svn/repos

The /srv/svn/repos on my system:
    drwxr-xr-x 2 svn svn 4,0K 16 mrt 11:23 conf
    drwxr-sr-x 6 svn svn 4,0K 23 mrt 10:00 db
    -r--r--r-- 1 svn svn 2 18 jan 23:30 format
    drwxr-xr-x 2 svn svn 4,0K 18 jan 23:30 hooks
    drwxr-xr-x 2 svn svn 4,0K 18 jan 23:30 locks
    -rw-r--r-- 1 svn svn 229 18 jan 23:30 README.txt
on the client system:
    drwxr-xr-x 2 svn cecil 4.0K 2011-03-22 14:56 conf
    drwxr-sr-x 6 svn cecil 4.0K 2011-03-22 14:56 db
    -r--r--r-- 1 svn cecil 2 2011-03-22 14:56 format
    drwxr-xr-x 2 svn cecil 4.0K 2011-03-22 14:56 hooks
    drwxr-xr-x 2 svn cecil 4.0K 2011-03-22 14:56 locks
    -rw-r--r-- 1 svn cecil 229 2011-03-22 14:56 README.txt

The group is different, but that should not make a difference I would
think. What could be happening here?

My version:
    svnserve, version 1.6.15 (r1038135)
the clients version:
    svnserve, version 1.6.12 (r955767)

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof