I always get the above error on calling:
osrm-routed.exe .\data\portugal-spain.osrm -a MLD

I prepared "portugal-spain.osrm" from "portugal-spain.osm.pbf", which I merged myselfe form "portugal-latest.osm.pbf" with "spain-latest.osm.pbf" using both, "osmium" and "osmosis".
If I use the prepared "portugal-latest.osrm" from the original file "portugal-latest.osm.pbf", everything works. So I guess it has to do with the merge-process. But this and the preperation of the data didn't show any errors - as fas as I can tell.

So I'm running out of ideas what exactly could cause this error.
Anyone has an idea? Or could it be a bug in some way?

Here are the commands I executed:
.\bin\osrm-extract .\data\portugal-spain.osm.pbf -p .\bin\CustomProfile.lua
.\bin\osrm-partition .\data\portugal-spain.osrm
.\bin\osrm-customize .\data\portugal-spain.osrm
.\bin\osrm-routed .\data\portugal-spain.osrm -a MLD

Thanks a lot for any hint!