FMC re-programming

J41 FMC: When using the FMC for standard flight operations from X to Y all works as intended. But when I try - during the flight - to delete (ERASE) the FPL and replace it by a new one, I fail. Example: On a flight from EDFM to EDDS (this is a short flight) I am located abeam EDRY, where I erase the flightplan and enter a direct to EDRY (which is about 20km away). Doing so the FMC shows my a distance of 2950NM. The ND (Map mode) does not show a line either. However, checking the CLOSEST AIRPORTS page, all data seem to be fine. What am I doing wrong? Miniaturansicht angehängter Grafiken