I haven't explored the actual source, but it seems likely to me that
Perl 5.8 has a small error in the NetBSD implementation of mkdir().

As was discussed here before, NetBSD mkdir(2) does not allow a
trailing slash delimiter and, unless I misunderstood, it is left to
the users of the function to remove such a slash if encountered.

I have installed the F-Prot virus checker for NetBSD and its mail
scanner kept crashing until I removed some gratuitous slashes in a
directory name.  Instead of me making corrections to the source of
scan-mail.pl, it would be preferable if Perl made allowance for the
NetBSD behaviour and my hope is that somebody with influence on Perl
development may be monitoring this list and will have this minor
niggle sorted out.

++L