My Gadget is blank as soon as I add the config parameter to my content, why is that?

Alright, so I'm trying to develop a gadget that can use a filter to display a certain information.

I am able to write a simple plugin and make a static view with it(wohoo) , but I'm stuck at the Config screen. Everytime I try to add a UserPref and add the config parameter the gadget becomes blank.
I even followed some tutorials(many, all I could find in fact) and it didn't work a single time, not even something simple as the refresh configuration seems to work.

Does anyone have an explanation?

Thanks in advance. =)