This is a fixed version of the prior posting with this name. Doug noted that it was broken under Windows.
from preamble:
"Change Set: RelativeZipExtractFix-nk Date: 16 December 2002 Author: Ned Konz Version: 3.4b
16 Dec: This fixes a problem with re-opening a zip in an ArchiveViewer under Windows (by opening zips read-only), as well as fixing extraction with subdirectories under Windows.
13 Dec: This ensures that zip extraction relative to a given directory works properly, and should eliminate the infinite recursion noted on the Mac.
It lacks AcornFileDirectory>>relativeNameFor: ; this should be added if necessary before adding to the update stream. "!