ZBrushCentral

maya atch render issues

hi guys im currently rendering out an animation in maya and im getting the following results " Error: The attribute ‘defaultRenderGlobals.putFrameBeforeExt’ is locked or connected and cannot be modified. //
// Error: The attribute ‘defaultRenderGlobals.periodInExt’ is locked or connected and cannot be modified. // "

any clue as it wont allow me to batch render my animation.