In the wacky world of TV broadcasting, there aren't any constants. This summer that's become painfully aware, as area viewers can't understand why some of the games that are listed to be aired, aren't.We're referring to Houston Astros and Texas Rangers games scheduled to appear on Fox Sports Net, Fox Family Channel, and Time Warner Cable's channel 19.You see, for the past few months, there's been some sort of scheduling snafu involving both entities. We don't know exactly what it's all about, but we do know that some games scheduled to be shown haven't been airing, and Time Warner folks are just as perplexed as we are as to why."We get calls about this all the time," said Time Warner's Lisa Thomas, who did her best to explain the situation