My question involves bankruptcy in the state of: Oregon

In 1997 I filed Chapter 7, and it was discharged in June 1997. Since then I have been contacted by a collections agency that says I incurred a debt in 1994. I did not know of this debt (or I would have listed it) and I read that under a 'no asset' bankruptcy in the Ninth Circuit that you can amend your bankruptcy to add a creditor. If I was not contacted about the debt until 2002, then again in 2008, can I still amend my bankruptcy to add the debt?