In short sale (waiting on response from lender) have been served with the foreclosure summons. Do I need to file answer?

Have been in constant communication with lender, calling every month making notes of each conversation. Placed house on market in March 2009 when we missed our first payment. Secured buyer in October 2009 and broker submitted all the paperwork to lender. It's November 2009 and we are still waiting to hear back from lender to see if the offer has been accepted. However, lender had already moved forward with foreclosure proceedings, we were served in mid-October. Do I need to file an answer to the foreclosure summons? Or do I need to wait to get the response from the short sale? If I don't file the answer won't they move forward quickly with the foreclosure and will that negate the short sale? Really confused on what to do? - Is this your question? Add additional information