The most common `vc-svn.el' issue is that:
    - distros include an Emacs 21 version in the subversion software
      package and put it in /usr/share/emacs/site-lisp/

    - emacs 22 and 23 have a newer version with a lot of changes in
      their non-site lisp directory, example:
      /usr/share/emacs/22.1/lisp/

    - emacs loads the site-lisp first, and thus the older library

Deletion of the old library, or explicit loading of the newer by
canonical file name is recommended.

Regards,
-timotheus