[Zope] Added Product Doesn't Show Up In ZMI

Hi All, I'm having a rather strange problem. I'm trying to get the Issue Dealer (http://www.nidelven-it.no/products/issue_dealer) product up-and-running on my Zope install (FreeBSD 4.11, Zope 2.7.1, Python 2.3.4). According to the Issue Dealer docs, I should simply be able to unzip it into the Products directory, restart Zope, and go, just like normal. I've done this, however, and nothing happens. Issue Dealer doesn't show up in /Control_Panel/Products, or the [Add] dropdown. No broken products, no nothing. Nothing looks at all unusual in the Products directory on the file system. I've tried rebooting the machine and restarting from the ZMI, to no avail. Has anyone seen this before? Any ideas? Thanks, Aaron