Why doesn't hardware detection find my printer?

[joe at actionline.com]

I have an HP Laserjet 4 Plus connected to my computer's parallel port, but
hardware detection (even after reboot) does not find it and I can't figure
out why. Hardware detection finds these:
- SATA controllers
- (E)IDE/ATA controllers
- USB controllers
- USB ports
- SMBus controller
- Bridges and system controllers
- Hard Disk
- CD/DVD burners
- Videocard
- Soundcard
- Processors
- Ethernet card
- Keyboard
- Mouse

Here are the other things I've tried, all seem to show the port:

$ lsmod | fgrep par
parport_pc             25092  0
parport                33964  2 ppdev,parport_pc

$ /sbin/modprobe lp
FATAL: Error inserting lp
(/lib/modules/2.6.26.8.tex3/kernel/drivers/char/lp.ko.gz): Operation not
permitted

$ cat /proc/ioports --- found 0378-037a : parport0

The cable connection is tight.

BIOS shows these options & selections:
Parallel Port (*) 378/IRQ7


What else can I try?