There is no problem here with ghosting & DGDK.
It is true that it was not working, but it was reported and fixed.
Sometimes it is hard to decide which command to use.
dbSetAlphaMappingOn : Makes object transparent with different modes
dbSetObjectTransparency : Sets how much the object is transparent
dbSetImageColorKey : Sets a colour for transparency
dbGhostObjectOn : Makes object transparent in 'ghosted' mode
Beware that dbGhostObjectOn needs a light to show the object, and the power of ghosting is set with dbFadeObject rather than with dbSetObjectTransparency.