prevent some references to non-existing variables
Merge remote-tracking branch 'origin/master' into 1.4.6

Conflicts:
	zp-core/404.php
	zp-core/template-functions.php

	modified:   zp-core/404.php
	modified:   zp-core/template-functions.php
	modified:   zp-core/zp-extensions/downloadList.php