Oops…
Trac detected an internal error: 
If you think this really should work and you can reproduce it, you should consider reporting this problem to the Trac team.

Go to http://trac.edgewall.org/ and create a new ticket where you describe the problem, how to reproduce it. Don't forget to include the Python traceback found below.

TracGuide — The Trac User and Administration Guide 

Python Traceback
Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/trac/web/main.py", line 406, in dispatch_request
    dispatcher.dispatch(req)
  File "/usr/lib/python2.5/site-packages/trac/web/main.py", line 191, in dispatch
    chosen_handler = self._pre_process_request(req, chosen_handler)
  File "/usr/lib/python2.5/site-packages/trac/web/main.py", line 263, in _pre_process_request
    chosen_handler = f.pre_process_request(req, chosen_handler)
  File "/usr/lib/python2.5/site-packages/trac/versioncontrol/api.py", line 73, in pre_process_request
    self.get_repository(req.authname).sync()
  File "/usr/lib/python2.5/site-packages/trac/versioncontrol/api.py", line 104, in get_repository
    repos = self._connector.get_repository(rtype, rdir, authname)
  File "/usr/lib/python2.5/site-packages/trac/versioncontrol/svn_fs.py", line 234, in get_repository
    repos = SubversionRepository(dir, None, self.log)
  File "/usr/lib/python2.5/site-packages/trac/versioncontrol/svn_fs.py", line 267, in __init__
    self.repos = repos.svn_repos_open(self.path, self.pool())
  File "/var/lib/python-support/python2.5/libsvn/repos.py", line 55, in svn_repos_open
    return apply(_repos.svn_repos_open, args)
SubversionException: ("Can't open file '/svn/srb2/format': Permission denied", 13)