FMC flightplan issue

I have scrolled through looking for a soloution to this problem but cant see to find anything ,I'm using the QW 757-200,
I create my flightplan through fsx flight planner and once I'm in the cockpit and select my FMC the following happens,i select 'LOAD ATC RTE' which then shows my departure airport and destination airport which is all fine then activate and exec and go through to the 'PREF INIT' and fill all of this in fine , the problem is when I get my runway from ATC and try to input into the 'DEPARR' on the FMC I just get a message saying 'NOT IN DATABASE' ??? any ideas any help would be great dying to fly this thing !! 😕