Subscribers to MLB.tv, Major League Baseball's paid game-broadcasting website, pay either $19.95 per month or $119.95 per year to watch live baseball on their computers. Theoretically, that is. So far this season all some fans have seen is a lot of swing-and-a-miss from MLB.tv and its technology provider, Microsoft. Switching to Microsoft's Silverlight, a supposed alternative to the Flash technology that runs YouTube and most other video sites, caused opening-day glitches for which the league's technocrats apologized Customers tell us it hasn't gotten much better since. Giants fans may be used to that kind of failure — watching Randy Winn, Bengie Molina and Ray Durham hit 3, 4, 5 will do that — but others are peeved.