One great thing about Zope is that you can move a Zope instance from one machine to another, and it just works... even if the other machine is on a different architecture or operating system. (case in point: I developed Tyrell's plone site on Mac OS X and copied it onto our Linux/Intel server... it just worked).

However, if you move between Windows and an operating system that uses forward slashes for path delimiters, like UNIX/Linux/BSD/OSX/etc, you need to make some minor edits in the CMF portal_skins configuration to change some relative paths from backslashes to forwardslashes, or vice versa.

This script from the ZopeLabs cookbooks makes that process very easy.

ZopeLabs: change skinpath after moving site