Ok, here's what's going on.

I have an HP LaserJet 4100 on an HP Jet Direct 3 port that is setup on a Windows 2000 Server (Domain Controller)

I have a PC in that location that is on the domain running Windows 2000 w/ SP4 & Adobe Acrobat v5, and setup to print to that printer.
Everything prints fine, except when the user prints a PDF document. It shrinks it to the upper left corner.
Verified all printing preferences, everything should be ok. But it's not.

We printed the same document to another HP LaserJet 4100 on the same network, and it prints fine.
We had another user try printing the same document from their PC to the first HP LaserJet 4100, and it also shrinks it.
The differences between them are that this PC is on Windows 98SE and Adobe Acrobat v4.0

So, we downloaded the latest HP drivers for the printer, installed them on the server. (We used the HP PCL 5e Driver)
If we install the PCL6 driver it messes up another application they use that is more critical than a PDF file.

Troubleshooting steps taken:

We have...
...deleted, reinstalled & shared the printer on the server (using the latest PCL5e driver)
...deleted & reinstalled the printer on the Windows 2000 PC from the server.
...uninstalled & reinstalled Adobe Acrobat reader 5
...repaired Internet Explorer 6 SP1
...ran System File Checker on Windows 2000
...installed all updates from Microsoft Windows Update site
...reinstalled Service Pack 4 for Windows 2000

The only thing left we haven't changed is the PCL5e to PCL6 driver. This may cause issues with another application that they use through a DOS emulator.

Is there anything else we're not thinking of?