Running on Debian Lenny, with Python 3.1.
The Python 2.5 version is OK.

~ $ python3 --version
Python 3.1.1+
~ $ python3 -m doctest
F..............
======================================================================
FAIL: Doctest: __main__.DebugRunner
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python3.1/doctest.py", line 2096, in runTest
    raise self.failureException(self.format_failure(new.getvalue()))
AssertionError: Failed doctest test for __main__.DebugRunner
  File "/usr/lib/python3.1/doctest.py", line 1644, in DebugRunner

----------------------------------------------------------------------
File "/usr/lib/python3.1/doctest.py", line 1712, in __main__.DebugRunner
Failed example:
    runner.run(test)
Expected:
    Traceback (most recent call last):
    ...
    doctest.UnexpectedException: <DocTest foo from foo.py:0 (2 examples)>
Got:
    Traceback (most recent call last):
      File "/usr/lib/python3.1/doctest.py", line 1243, in __run
        compileflags, 1), test.globs)
      File "<doctest __main__.DebugRunner[15]>", line 1, in <module>
        runner.run(test)
      File "/usr/lib/python3.1/doctest.py", line 1736, in run
        r = DocTestRunner.run(self, test, compileflags, out, False)
      File "/usr/lib/python3.1/doctest.py", line 1375, in run
        return self.__run(test, compileflags, out)
      File "/usr/lib/python3.1/doctest.py", line 1296, in __run
        exception)
      File "/usr/lib/python3.1/doctest.py", line 1742, in
report_unexpected_exception
        raise UnexpectedException(test, example, exc_info)
    UnexpectedException: <DocTest foo from foo.py:0 (2 examples)>


----------------------------------------------------------------------
Ran 15 tests in 0.015s

FAILED (failures=1)
~ $