The owner of the financially-troubled Riviera hotel-casino on the Strip has missed another interest payment on its debt. Riviera Holdings Corp. says it missed making a payment on its 245-million-dollar credit facility that was due at the end of last month. Previously, Riviera failed to make a four-million-dollar interest payment on March 30th. The company noted reduced business at its properties in Las Vegas and Colorado due to the recession and had indicated bankruptcy protection had not been ruled out. However, the company says it continues with its lender Wachovia Bank.