Really irritating keyboard behavior.

I'm having a big problem with my brand-shiny-new Toshiba Satellite 2400 laptop, set up with Debian woody. The keyboard works fine at the console, but as soon as I switch into X it gets "bouncy" and sporadically doubles letters, so that "dollar" is likely to come out looking like "ddoolaar", which irritates me to the point that I would describe the machine as unusable.

I'm assuming, since it works fine at the terminal, that there is some way to configure X (4) into sanity. Anybody know what it might be?

Update: Problem fixed, with many thanks to this guy and his Tecra 9000. Hooray, community!