Hmmm.. first time I heard of this campaign.
I see Lord of the Land is in the MG mod center, but not the other 2. I downloaded them, but haven't played them yet.
I started campaign 2, and got this error
*ERROR* [2016-06-10 19:56:53] In [/home/andy/src/megaglest-3.12.0/source/glest_game/types/skill_type.cpp::load Line 485] WARNING CANNOT LOAD MODEL [/home/andy/.megaglest/scenarios/campaign_2:_search_for_allies/megapack_/factions/tech/units/swordman_/models/guard_attacking.g3d] for parentLoader [/home/andy/.megaglest/scenarios/campaign_2:_search_for_allies/megapack_/factions/tech/units/swordman_/swordman_.xml]
But it continued without crashing.
campaign 1 (Lord of the Land) and 3 gave me similar errors.