From what I have garnered on the Internet so far, it means the hob is not sensing the touch pad. One resource said to try and clean the touch pad, but that did not solve my problem . One other resource said that Fault code ER22 means The control panel is filthy or has water on it and the solution is to clean the control panel (Did not work for me either). In any event, try to switch the hob off and see if it solves the problem. You may also need to call out a technician if DIY does not work (i am currently waiting for a technician to check it out).
Emmanuel, January 2014