Voting Problems in Pennsylvania

The biggest problem we’re hearing about so far today is in Pennsylvania, where “massive problems” are being reported with voting machines in 37 counties. The Santorum campaign says that in some instances, votes for a candidate are being recorded for another candidate. I don’t understand, however, how this would be visible to the voter.
A poster at the Election 2006 site on the Power Line Forum recounts his experience in central Pennsylvania:

I showed up at my polling location at 7:05 this morning. There was already a line and it didn