I don't understand this error

I was working on a new MA mission, where the enemy group was supposed to be the cast of a new fantasy movie. I filled the group with a variety of standard critters with appropriate costumes (some redcaps, CoT, etc), but now I can't publish the arc. I am getting the following error, which I don't understand:

First off, the praetorians are unlockables, make sure you have them unlocked on the account you want to publish with. Second, try removing the invalid critters and reselecting them, sometimes patches wreak havoc on standard critters in custom groups. If that doesn't work...(insert longwinded rant about heavy-handed "fixes" to stop farming impacting authors and limiting creativity).

Ahhh, I think you might have it. I think I originally was working on the mish with my first acct, but tried to publish with the 2nd. I might have to unlock that group on the 2nd acct, or publish w/ the first.

Thanks, Eva.