Importing is a bit hit and miss - Spawnmaster uses long zone names mostly, so say - Eastern Wastes does not correspond to Alertmasters eastwastestwo short zone name, even though the list of spawns is actually for the ToV version of Eastern Wastes. When I run into that, I generally open the ini for spawnmaster, copy the list of spawns, then paste them into ini for alertmaster, and renumber the spawns from 1 - x, since spawnmaster also numbers spawns from 0 - x. Add in the zone by shortname ([eastwastestwo]), save Alertmaster.ini, and it should now keep the info for the zone.
the error you got is because Alertmaster doesn't have that command as part of it.