I've set up a git repository, uploaded a diff that I'd like to review, but getting:

Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/ReviewBoard-1.0rc2.1-
py2.5.egg/reviewboard/diffviewer/views.py", line 152, in view_diff
    interdiffset, highlighting, True)
  File "/usr/lib/python2.5/site-packages/ReviewBoard-1.0rc2.1-
py2.5.egg/reviewboard/diffviewer/diffutils.py", line 620, in get_diff_files
    large_data=True)
  File "/usr/lib/python2.5/site-packages/Djblets-0.5rc1.1-py2.5.egg/djblets/util/misc.py", line 
143, in cache_memoize
    data = lookup_callable()
  File "/usr/lib/python2.5/site-packages/ReviewBoard-1.0rc2.1-
py2.5.egg/reviewboard/diffviewer/diffutils.py", line 619, in <lambda>
    enable_syntax_highlighting),
  File "/usr/lib/python2.5/site-packages/ReviewBoard-1.0rc2.1-
py2.5.egg/reviewboard/diffviewer/diffutils.py", line 341, in get_chunks
    old = get_original_file(filediff)
  File "/usr/lib/python2.5/site-packages/ReviewBoard-1.0rc2.1-
py2.5.egg/reviewboard/diffviewer/diffutils.py", line 248, in get_original_file
    large_data=True)[0]
  File "/usr/lib/python2.5/site-packages/Djblets-0.5rc1.1-py2.5.egg/djblets/util/misc.py", line 
143, in cache_memoize
    data = lookup_callable()
  File "/usr/lib/python2.5/site-packages/ReviewBoard-1.0rc2.1-
py2.5.egg/reviewboard/diffviewer/diffutils.py", line 247, in <lambda>
    data = cache_memoize(key, lambda: [fetch_file(file, revision)],
  File "/usr/lib/python2.5/site-packages/ReviewBoard-1.0rc2.1-
py2.5.egg/reviewboard/diffviewer/diffutils.py", line 227, in fetch_file
    data = tool.get_file(file, revision)
  File "/usr/lib/python2.5/site-packages/ReviewBoard-1.0rc2.1-
py2.5.egg/reviewboard/scmtools/git.py", line 32, in get_file
    return self.client.cat_file(self._resolve_head(revision, path))
  File "/usr/lib/python2.5/site-packages/ReviewBoard-1.0rc2.1-
py2.5.egg/reviewboard/scmtools/git.py", line 195, in cat_file
    raise SCMError(errmsg)
SCMError: fatal: Not a git repository: '/path/to/repository/'

But /path/to/repository is a perfectly valid Git repository.