Your best bet is just to throw the thing away. However, if you are handy with a screwdriver, here is an almost certain fix:
Making sure the unit is unplugged, remove the bottom metal plate. A grounding wire is attached underneath so be sure to remove that as well. Set plate aside. You will see several circuit boards. Locate the one that has the small, round, silver battery on it. Next pull off all the connecting cables. Don't worry about which goes where as they only fit the way they came out. Carefully remove the board from the unit. It is held in place by plastic clips that you can gently pry back. Taking a small screwdriver, carefully lift the battery up a bit. It is soldered in place so be careful not to break it off. Next you need to short the battery momentarily. Do this by placing the screwdriver across the two metal tabs that are soldered to the battery. If your screwdriver is too small, use a bent paper clip to short the terminals. Put everything back together. Load film and paper before plugging it back in. When you plug it in it should come back on showing the date. The memory module sometimes refuses to reset after an error and the battery backup keeps this memory. Often the start/stop reset function will not reset so you need to short out the battery momentarily to clear the memory. Hope this helps.
L. Carlin, June 2007