Capmark Financial Group Inc. (CPFNG), one of the key commercial real-estate lenders in the U.S., along with some of its subsidiaries has filed Chapter 11 protection. The filing adds to the lingering concern that the commercial real-estate market is still struggling.  The company seeks to be allowed to continue to pay its vendors and salaries, and protect the businesses with its customers and partners.  Capmark was created in March 2006 through a leveraged buyout of the commercial real estate assets of General Motors' finance arm GMAC. Earlier this year also, the company had indicated that it might file for bankruptcy due to deteriorating conditions in the financial and commercial real estate markets and capital inadequacy.  Capmark is currently negotiating the terms of the bankruptcy with its creditors, which include Citigroup Inc. (C) and JPMorgan Chase & Co. (JPM) among others.  Capmark ...