[Zope] where is 'png4' which is required for installation?

OR is this a problem with FreeBSD? I've tried about everything I can think of to get this installed on FreeBSD/i386 (although it seems to be properly installed in FreeBSD/Alpha,I gave up trying to get it to actually **work** on the Alpha after I got no reply to questions about it) thanks, craig craig@cheetahusa.net