When I try to open it, I get a screen that says that there is no HP device detected. Yet I have my HP Deskjet 6940, connected via USB, up and working.

Someone seemed to post the same problem (with a different model HP printer) on another forum and got no help.

Is this possibly a bug that needs to be reported?

TIA

Edit: Actually, I found the answer. The version of HPLIP installed was 0.9.7 and too old to support my printer and I installed the printer incorrectly.
I had to go to hplip sourceforge page and download the latest version of HPLIP, uninstall through Synaptic all things HPLIP already installed, then manually install the new version per the instructions at the sourceforge page for Ubuntu 6.06 (leaving out the 'sudo' command, of course).

As for installing the printer properly, I clicked "Add New Printer", checked 'local', then at the ports page chose the printer for 'others', where you may see the serial number of the printer listed. Then I continued on as normal, choosing Deskjet 6940 hpijs.

Hope this helps someone with this same problem.