Engineered Wood Floor onto Chip Board - Do I need DPM

Hi Guys

Just a quick one.

Im laying an engineered oak floor on to a chipboard sub floor (just stripped parquet off it - that was interesting..) The flooring shop sold me some DPM to lay under the underlay (i think, correct me if im wrong) But I have been looking around on the net and am reading that i only need to lay the DPM on top of a concrete floor?

Can anyone clarify?

Think I answered my question here: http://woodyoulike.typepad.com/tips/2006/09/type_of_underfl.html

Glad to have been of service