There was 1 error:
rmdir(C:\Documents and Settings\Administrator\phpbb3\tests\cache/../tmp/cache/):
There were 6 failures:
Failed asserting that <integer:0> matches expected <integer:2>.
Failed asserting that <null> is an instance of class "phpbb_cron_task_wrapper".
Failed asserting that two arrays are equal.
-  => phpbb_cron_task_testmod_simple_ready
The first error is probably irrelevant.
Tests fail with a good reason - cron on windows was broken due to directory separator differences.