For those using the Zip pecl pakcage, Pierre has a quick update you'll need to download to resolve some pathing issues that were found.
A little release to help windows users to work with broken zip entries named like "a/b//c.txt". PHP 5.1+ mkdir does not support such path on windows and simply refuses to create the base dir. The """bug""" has been fixed in php 5.2 or earlier and a work around exists in zip itself for earlier versions.
You can grab this latest update directly from the project's homepage.