It seems that Acer has not published cpu support list for that oem model motherboard, so there is really no way to be sure except to try it out. But as pentium E2140 is core2duo (based on Allendale core) processor, I would say that it should work.
Hm, that's too bad.
Are you sure about the Pentium E2140 being Core2Duo, though? I found this article: http://en.wikipedia.org/wiki/Conroe_(microprocessor)
, and it says the E2xxx are all Pentium Dual Core's.
(not sure if this is the right way to reply to your message, sorry if it's wrong.)