The command completed:sudo lpadmin -p PRINTQ -v "usb://HP/Photosmart%20C3100%20series?serial=CN668B721G04KV&interface=1" -E -m "drv:///hpcups.drv/hp-photosmart_c3100_series.ppd"
Then the print command completed: lp -d PRINTQ /etc/nsswitch.conf request id is PRINTQ-544 (1 file(s))But then paper was pulled and the printing stopped and the power button light is flashing. (No error light.)
Tried again, and this time it worked fine. What does this tell you?