Additional information on the error status. The lights on the front panel of the LaserJet 1200 printer remain green, as in normal ready state. There are no blinking or amber lights. The only error indication I get is by going to Control Panel-Printers-HP 1200-documents. At that point document status indicates "error" and there is no printing. I now notice that if at that point I power down the HP 1200, and then power back up, documents in the queue do in fact print out. Shortly after, however, the printer returns to the error status as reported above.
I am now beginning to believe that there is a printer malfunction and that all is OK with the USB port and interface.