Most error codes are designed into this machine's controller to inform you that the machine won't fill or won't fill high enough. This feature prevents damage to the wash pump >AND< let's you know that "HEY! I can't wash your dishes properly so I'm stopping until you fix me!"
However, water supply is usually NOT the problem. The controller goes into displaying an error code because it's not "seeing" water at their proper levels. That's usually due to the sensing probes being so dirty that they have become "insulated" FROM sensing the water level.
What you need to do is to clean the metal water probes (there's three of them) with a Scotchbrite pad to remove any lime or soapy buildup. If that doesn't solve it, then make sure the water supply IS still on FULLY and there are no restrictions (such as kinked supply hose) affecting water flow into the machine.
If your problem still exists, then you will need to call Hobart to have your machine serviced. Before doing so, I suggest consulting the instruction manual for your machine. If you can't find it, go to http://www.hobartcorp.com/. Click the SERVICE & PARTS tab. Then the MANUALS & SUPPORT tab. follow the instructions for registering, then you can find and download a manual.