Yes.  There was actually a case on point back in the eighties.  In Glickman v. Brown (21 Mass. App. Ct. 229) the court held that if a real estate agent affirmatively misrepresents the truth, that is an unfair and deceptive act under Massachusetts' consumer protection law Chapter 93A).  Of course, the key would be proving the agent knew of the cracked flue. 
 
However, in In Piers v. Wheeler and Taylor, Inc. 8 Mass. Law Reporter 410 (1998), the court held that a seller and real estate agent may be liable under 93A because they made statements about a home (free of lead paint) without verifying that fact.  In fact, the court called such behavior "willful misconduct."  So, in your case, even if the real estate agent did not know about the problem, she was obligated to either say nothing in response to your question and defer to your home inspector or to verify the substance of her claim.  You may want to discuss this matter with an attorney in your area who does consumer protection work.  Good luck.  Good luck, and please tell your friends about The Forum.