I have been using similar freeware software to play Guild Wars on a PlayStation 2 pad since May '05. All it really does is change your input device from mouse/keyboard to gamepad/joystick etc. Both the software you linked and the software I use allow for macros, or multiple key presses to a single button. Neither that software nor the program I use appear to allow for automatic input, however. At least mine does not.
I'll just refer you to necrhonius's post in regards to whether it can result in a ban. Technically, it does violate the EULA, but the risk is mine to take, and I have. Personally, I think the risk is miniscule, but don't blame me if for some reason I am proven wrong. For one thing, there's not really any way for ANet to detect it that I am aware of, and it does not afford any advantage.
If anyone is interested in a free alternative to the OP's link, I'll post it. I can confirm it's spyware/virus/trojan etc. free, and it does work on GW.
edit: There's actually a thread in Community Works for GW with an XBOX360 pad here:
http://www.guildwarsguru.com/forum/s...php?t=10210954
Obviously, I prefer my configuration to the one in that thread. More controls, for one.