Thread:Extension talk:DynamicPageList (Wikimedia)/Fatal error: Cannot redeclare wfDynamicPageList()/reply

You have both DynamicPageList (Wikimedia) and DynamicPageList (Third party) installed. They seem to be conflicting with each other. (I think there's some setting in the third party version to stop it from trying to impinge on the Wikimedia version's function. Not sure).