After departing on the ATL Runway 8R RNAV; an Air Carrier's FMS dropped the active waypoint and sequenced the aircraft to the next point. The crew requested a vector and believe that this anomaly has occurred previously.

Narrative

Departing via the RNAV SID from Runway 8R at ATL; at approximately 500 FT the Tower Controller gave us a clearance to precede directly to the second fix. Captain selected that fix in the FMS then asked that I verify that it was depicted correctly. I verified that it was indeed depicted correctly on the display and in the box; and he proceeded to execute it. We then both verified that the dashed white line turned to a magenta line to that fix. We had by then reached 1;000 FT and upon request; the Captain dialed in half rate; climb power. While he was doing that I noticed that the Flight Director was commanding a high bank angle of turn for what should have been a fairly small amount of heading change; and so while leveling the wings I informed the Captain that something was wrong with the FMS. As we both looked at it we immediately saw that what should have been the active waypoint had been dropped and the FMS was trying to steer directly to the next fix which was approximately 90 degrees off our wing. Captain immediately informed the Tower Controller that we were RNAV unable and that our FMS had malfunctioned. The Tower Controller gave us a heading (which was very close to the heading we had already established) and informed us that there had been no conflict of any kind. To our knowledge; no procedural mistakes were made by the crew. I have heard from other pilots that this is a reoccurring problem on this departure. I would suggest determining if there is a history of problems with this departure and if so terminating this RNAV departure procedure if a history is discovered.