Error: asSlave: human must be a valid SlaveState object

Tried fiddling with different things in my previous save but I keep getting this particular error when I end week. Running any variation of BC doesn't get me anywhere. What am I missing? What could be causing this?

Passage: Slave Assignments Report; Version: 1258#958525cc

Error: asSlave: human must be a valid SlaveState object globalThis.asSlave@/FC_pregmod.html line 623725 > eval:405054:36 globalThis.setPregType@/FC_pregmod.html line 623725 > eval:380474:90 globalThis.tryKnockMeUp@/FC_pregmod.html line 623725 > eval:380925:24 useDick@/FC_pregmod.html line 623725 > eval:131798:16 saPleaseYou@/FC_pregmod.html line 623725 > eval:129092:12 fullReport@/FC_pregmod.html line 623725 > eval:101061:32 App.EndWeek.penthouseReport@/FC_pregmod.html line 623725 > eval:100981:21 App.EndWeek.slaveAssignmentReport@/FC_pregmod.html line 623725 > eval:157021:39 @/FC_pregmod.html line 623725 > eval:2770:25 render@/FC_pregmod.html line 623725 > eval:1462:16 enginePlay@/FC_pregmod.html:623725:257947 advance@/FC_pregmod.html line 623725 > eval:83756:11 doEndWeek@/FC_pregmod.html line 623725 > eval:83467:3