The obvious thing you are missing is in bold writing below and in a couple of my tutorials:
First make sure the meta is available.
Checking the Map Thread Finder for the 890 maps, there is no meta available for the Europe_West_890_4224 map. That's why a .dct file is not being created.
So no matter what you do, you cannot activate this particular map. You need to choose a map which has meta.
Instead, download the Western_Europe_890_4224 map (not to be confused with the "Europe_West" map). It is compatible with your 7.903 navcore, and there is already meta for it, so it can be activated. Download it from the following thread: