Hi Bobby,
sorry for let you waiting...
Your verbose output suggest something is wrong with the filename
generation - "file name '(null)'..."
If you use tiling_ns parameter blast2dem extract the file endings out of the given filename.
Extend your command with a filename does the job:
blast2dem -v -i *.las -merged -kill 200 -nodata -9999 -tiling_ns crater 500
-keep_class 2 14 20 -step 1.0 -cores 14 -odir .\BND_DEM\BLAST -oimg
-epsg 6343
-o foo.imgJochen