When I try to delete a "Route Discontinuity" on the FMC, it says Invalid Delete and I wan't to start the flight A.S.A.P

 

But with the Problem, my plane will go bezerk!

on the legs page, select the leg directly under the line that has the [][][][] and then click the line select key for the [][][][] to replace it. You can't delete the [][][][] in itself.

Of which aircraft are you talking about?