Talk about a Maalox moment: this is the sort of major news that, coming as it does right before this week’s upfront presentations by the networks, can give CW co-bosses Les Moonves (CBS) and Barry Meyer (Warner Bros) heartburn. According to the business wires, Pappas Telecasting Inc, the largest privately-held commercial broadcast operator in the U.S. filed for Chapter 11 Saturday with plans to sell its 30 TV stations under bankruptcy court protection. Pappas cited “the extremely difficult business climate for television stations across the country” in papers filed with the U.S. Bankruptcy Court. The Fresno, Calif.-based company’s TV stations are affiliated with a number of broadcasters, and include two big Fox affiliates in Fresno and Omaha. But Pappas specifically blamed the “poor ratings of the CW Network” for some of the financial trouble that forced it into bankruptcy. Also cites as problems are the economic downturn, plunging advertising and the cost of converting from analog to digital TV broadcasting.