check the brushes in the gearbox they may have worn down.
Remove battery, remove battery tray, u should see the connectors for the brushes (be careful not to damage the holders taking them out).
Other causes inlcude low fluid level, sensors on accelerator pedal, sensor on gearbox (cant remember where exactly though), faulty control unit (behind centre console) also check the fuse for the cvt control unit(under bonnet) and also relay(under bonnet)
Hope something helps
chris, April 2008