NIAGARA FALLS, N.Y., May 13 More than 2,000 people in the city of Niagara Falls, N.Y., were erroneously sent final warnings for traffic tickets, causing widespread confusion.WGRZ-TV in Buffalo, N.Y., reported that warnings were mailed out regarding tickets from as long ago as 1991."The city of Niagara Falls mailed out thousands of traffic tickets last week," said an area resident. "Some date back to 1991. I received one from 2003 for my 31-foot sailboat ticketed in a fire zone. How can you defend a traffic ticket from 1991?" The city reportedly is sending out letters to explain what happened. Authorities expect the error to cost the city about $1,700.Copyright 2007 by UPI