In households across the Chicago area today, people were asking, "Where's the Tribune?" A computer glitch delayed production of the Chicago Tribune this morning, meaning today's paper was released about four hours late and much thinner than originally planned. General Manager Dick Malone says technicians had upgraded their computers yesterday and thought the system was working. But when it was time to print early this morning, he says the system failed. The newspaper that finally printed is about 20 pages smaller than planned. Customers who don't receive delivery today will get a credit.