I could print without any problems with Knoppix 3.7. However, I couldn’t print anything since Knoppix 3.8 went out. Also, I noticed some folks are having the same problems with their HP machines. Here’s how I finally was enable to print.
Boot Knoppix and right after Konqueror salutes you unplug your USB printer. Wait for like 3 seconds and replug it. Wait another 3 seconds. Presto, you can use any tool to configure your printer.
I’m pretty sure you can do the same to any other USB device that 3.9 won’t work with after the boot setup is done. This solution came out after I couldn’t mount my portable USB drive, even if an icon showed up (uba1) in the desktop.
I know everybody is now worry about to get Kno 4.0, but in the meantime we’re using Kno 3.9. I hope this will help to anyone.
P.D: I really mean it with unplug, replug right after KDE and konqueror load, I tried to load other program, then un/re/plug and it didn't work.
Lat

Dell 6P85J 4TB ST4000NM0063 7.2k 6Gb/s 3.5� SAS SED Hard Drive with Tray
$39.99
Western Digital HUS726T4TAL5204 4TB 7.2K SAS 12Gb/s 3.5" 512e HDD NetApp X375A
$64.00
Tested WD Ultrastar DC HC520 12TB 7.2K RPM SATA 6Gb/s 3.5" HDD HUH721212ALN600
$239.99
HGST Ultrastar HUS726040AL5210 4TB 7200RPM SAS 12Gb/s Enterprise HDD
$41.00
Seagate Barracuda ST1000DM003 1 TB SATA III 3.5 in Desktop Hard Drive
$23.99
Dell ST6000NM0034 1HT27Z-150 NWCCG 6TB SAS 3.5 7.2K ENTERPRISE SERVER DRIVE
$68.99
Toshiba DT01ACA100 1 TB 3.5" SATA III 3.5 in Desktop Hard Drive
$24.99
Seagate ST3000NM0005 HDD 3TB SATA 6Gb/s 7.2K 3.5" 512 b/s
$59.00
Seagate ST8000NM0075 Enterprise Capacity 3.5 HDD 8TB SAS Hard Drive 8TB EXOS
$184.99
Western Digital 1TB 3.5" SATA III 7200RPM Desktop Hard Drive
$34.99