pg8 beta3 Win32: after dropping db directory is not removed

Hi,

Most (but not all) of the time when I drop a database I receive the
following warning:

WARNING: could not remove database directory "c:/program
files/PostgreSQL/8.0.0-beta3-dev1/data/base/XXXXX"

Where XXXXX is the directory name of for the database being dropped. It's
not a really big deal, since all but one of the data files are removed, and
if the postmaster service is stopped, the directory and last file can be
removed.

Is this a bug?