The Device URI is completely incorrect for your printer, as socket:// is for a network (connected by ethernet) printer but, please correct me if I'm wrong, yours is a parallel printer.
Yes, that is correct. It is a parallel printer. How do I go about correcting this?
Run hp-toolbox from a terminal and post the output.
The first time I ran this I got this:
[buck@localhost ~]$ hp-toolbox
HP Linux Imaging and Printing System (ver. 3.12.9)
HP Device Manager ver. 15.0
Copyright (c) 2001-14 Hewlett-Packard Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.
HP Linux Imaging and Printing System (ver. 3.12.9)
System Tray Status Service ver. 2.0
Copyright (c) 2001-14 Hewlett-Packard Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.
/usr/lib/python2.6/site-packages/gtk-2.0/gtk/__init__.py:127: RuntimeWarning: PyOS_InputHook is not available for interactive use of PyGTK
set_interactive(1)
[buck@localhost ~]$
A box (Refreshing Device List - HP Device Manager) came up telling me there were no installed HP devices found with three methods as to how to set up a new device. Then at the bottom, it says, "
Note: Only devices installed with the hp: or hpfax: CUPS backend will appear in the Device Manager." There it gives me three options: 1. Set up device . . ., 2. CUPS Web Interface, and 3. Close. When I closed that box and re-ran "hp-toolbox" I just got this:
[buck@localhost ~]$ hp-toolbox
HP Linux Imaging and Printing System (ver. 3.12.9)
HP Device Manager ver. 15.0
Copyright (c) 2001-14 Hewlett-Packard Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.
And I get a black cursor and nothing else happens.
It appears that your user does not have any group membership because my output shows .....
--------------
| PERMISSION |
--------------
groups user-groups Required - - OK user sys disk lp wheel floppy tape cdrom usb cdwriter audio video dialout users apache usbmux machines mpd pulse-access mysql polkituser fuse vboxusers[/color][/s]
For some reason, the rest of this does not show up, but I did go in and add 'lp' to my user group.
Sorry, only now realised the hp-check was run as root and not as user ........ 
Does this matter? I ran per German Tux's suggestion.