It's Proph from ZG.
I'm also the guy who posted the thread about screen problems, I still need to register here. Too lazy. 
I tried what you said and my dpad worked properly, no spazzing in Excel.
However, I did adjust my key repeat settings a bit, so maybe you should try that and see if it helps.
Settings->Buttons->Up/Down Control
I currently have Delay set to about 2.5 notches from the left, and Repeat set to the 3rd notch from the left.
Seems like every PDA company has problems with quality control at their factories these days.
