Tuesday 06 October 2009 5:57:36 am

The reason PHP 5.2.9 is not recommended is that it has a ugly flaw in array_unique() function. This isn't 4.2 specific, It affects all eZ Publish 4.x versions!
So you should upgrade to latest PHP 5.2.x (as of writing: 5.2.11) version which works good on both of them( 4.0 and 4.2).

eZ Online Editor 5: http://projects.ez.no/ezoe || eZJSCore (Ajax): http://projects.ez.no/ezjscore || eZ Publish EE http://ez.no/eZPublish/eZ-Publish-Enterprise-Subscription
@: http://twitter.com/andrerom