Not sure how much you have changed on your system, but try the following.
as root delete the following files... (use the wildcard to get rid of .new or .default ones as well.
Then (still as root)
In gslapt install cups version 1.4.6
Download this new hplip that vector made ... and install it.http://vectorlinux.osuosl.org/vec7/hplip-3.11.7-i586-2vl70.txz
You should now have some new drivers for your printer
as root do
lsmod | grep usblp
is you see the module then good. You need it, with this cups version. I think it was configured to use it. Without it, it will not see usb.
If you do not see it then... (also as root)
Make sure you have not blacklisted it. Then...
To set up the printer use "Manage Printing" in the system menu. It will start the cups interface and under the administration tab you can add a printer.
About the thrid step in you can select the ppd. You may have to play with a couple different ones for best result but for me it was the one of the ones with hpijs in the title.