Your friend should first try Repairing Permissions. She needs to find "Disk Utility", which is in the Utilities folder within the Applications folder. Click on the top Hard Drive icon, click "Verify Permissions", which will bring up a load of stuff. When it has finished, click "Repair Permissions". When it has finished, quit Disk Utility.
If this doesn't fix the problem, check that she has the latest version(s) of the software. Panther (System 10.3) goes up to 10.3.9, easily downloaded via "Software Update" on the Apple menu. The latest version of the
HP 950 software is 7.3.1
It's likely that the permissions have become a little muddled. Checking the permissions from time-to-time is the only disk maintenance required on a Mac. They can go awry when new software is installed, for example. If your friend has never repaired the permissions, this could well be the source of teh problem.