Error 5 is a charging error. This error can happen if the iRobot Roomba is not placed correctly on its home base. The robot should dock itself on the home base and should not be manually set on the home base. This will help prevent error 5.
If this error occurs, please try resetting your robot by pressing the Dock and the Spot buttons at the same time for at least 15 seconds. Once you release the buttons you should hear a tune stating that the robot has been reset. Then you must plug the charger directly in the Roomba and not use the home base. Fully charge the robot for at least 16 hours and see if the error goes away and the Roomba is able to charge.
It is also possible that the yellow battery pull tab has not been released properly from the battery compartment. If the error does not go away after the reset and charging directly in the Roomba you may try unscrewing the side brush and the four screws on the bottom of the Roomba in order to remove the bottom plate. You may then take out the battery and verify if a part of the yellow battery pull tab remained in the Roomba battery compartment.
If this error has not ceased after several resets and charging cycles and you have bought your robot at RobotShop, send us a message via our Support Center.