May 15, 2008 - Former NBA star Charles Barkley has retired his debt to a Las Vegas Strip casino that sued him after he failed to pay $400,000 in gambling loans. But the civil lawsuit remains open, and it's going to cost Sir Charles $40,000 more to get out of the legal doghouse. Barkley, a basketball analyst for Turner Network Television, said in a statement released Tuesday by TNT that he didn't know about…