I have solved the problem on my own.

To solve this or similar problem, you have to open save manually using text editor (my favorite is PSPad) and make following substitutions:

MeleeWeapon_Maul -> CE_Melee_Maul
MeleeWeapon_Glaive -> CE_Melee_Halberd
MeleeWeapon_Zweihander -> CE_Melee_Zweihander
CE_Gun_crossbow -> CE_Gun_Crossbow
CE_Gun_TacFifty -> CE_Gun_HecateTwo

It doesn't have to be everything. These changes were enough in my case.