I've had that happen to my laptop before. I'm not sure why exactly, but here's what I'd suggest you do:
1) Firstly... POWERCYCLE. Shut down your computer (not Standby or Hibernate,) and turn it back on again after a few seconds. Computers are finicky sometimes, and most problems can be solved merely by powercycling. I myself fixed a problem today when my laptop came out of Standby and wouldn't obtain a proper IP address from my wireless router... I turned my laptop off and on again, and *yay* it works fine.
2) The Synaptics Pointing Device Driver is the driver for your laptop's touchpad. Does your touchpad work properly? I have a Toshiba Satellite L305, and Toshiba's Synaptics touchpad driver has an option in the mouse settings to DISABLE the Touchpad when I plug in my USB mouse (The drivers from Synaptics' website don't have that option, for some reason.)
I want it to do that, but there's a checkbox where that feature can be enabled/disabled in my mouse settings... which leads to:
3) Does the error you mentioned come up in a window or does it pop up as a tooltip from your System Tray? I know that when my USB mouse is plugged in, the Touchpad icon in my system tray (if I have it displayed) has a big red
X in it, because of the previously mentioned setting. Does the error come up when you plug in your external mouse?
Personally, my money is on powercycling. I bet that fixes it. If not, and you want to reinstall your touchpad drivers, do so from your Laptop manufacturer's site not from Synaptics.