Go to Start -> programs -> Bamboo and run the tablet preference utility. Select to remove the settings for all users, then test the tablet. If that does not succeed, download and install the 5.24 driver version from this site.
The problem may be that SAI detects information about 2 tablets. It always wants to get the pressure information from the first installed tablet, while coordinates are accepted also from the second tablet. If you disable the not needed driver (stop the service 'TabletServiceWacom' for Intuos, 'TabletServicePen' for Bamboo), you may still have to reset the driver (remove the tablet preferences with the utilities from Start menu -> Bamboo/Wacom Tablet).