Ok. I have tried different things and my results are:
1. My problem is related to 1BetterMusicScript
2. When changing the following from BMS 2.3:
BEGIN MenuMode 	
	   if ( GetGameRestarted && state )
		   if ( emcCreatePlaylist Loading "Data\Music\Loading\*.*" )
			   set state to 3
			   emcChangePlaylist 0 Loading
			   emcChangePlaylist 1 Loading
			   emcChangePlaylist 2 Loading
		   endif
	   endif
	   if ( GetGameLoaded )
		   set state to 3
	   endif
in the following from BMS 2.1:
BEGIN MenuMode 	
	if ( GetGameRestarted && state )	
		set state to 3
		if ( emcCreatePlaylist Loading "Data\Music\Loading\*.*" )
			emcChangePlaylist 0 Loading
			emcChangePlaylist 1 Loading
			emcChangePlaylist 2 Loading
		endif
	endif
it is working as it should be.
But what does that exactly mean? And why am I the only one for whom this leads to BMS not working?
Thanks again for helping (I feel we are close to defeat the problem 

 )