I have a model that I was working fine in OMEdit.  I then have second, more complex model, extended from that one.  The first model was working, until I made a small change in it.  Now, I am getting the following cryptic error when I try to run the first model. 

[:0:0-0:0] Error: Internal error ./Compiler/BackEnd/SimCodeUtil.mo: function createSimCode failed [Transformation from optimised DAE to simulation code structure failed]
[:0:0-0:0] Error: Internal error ./Compiler/BackEnd/SimCodeUtil.mo: function createEquationsForSystem1 failed for component torn nonlinear Equationsystem{{{269:161}, {316:337}, {281:162}, {270:160}, {271:163}, {272:174}, {276:165}, {277:132}, {273:164}, {274:122}, {275:121}, {268:128}, {257:48}, {261:63}, {262:33}, {263:32}, {264:61}, {265:44}, {266:310}, {267:311}, {258:30}, {259:313}, {260:312}, {250:8}, {251:5}, {252:4}, {253:7}, {254:6}, {255:314}, {256:324}, {282:187}, {283:184}, {284:183}, {278:186}, {279:185}, {280:308}, {249:227}, {246:242}, {245:212}, {244:211}, {243:240}, {242:223}, {241:304}, {240:305}, {247:209}, {248:307}, {239:306}, {238:297}},
{237:166} Size: 1
[:0:0-0:0] Error: Internal error ./Compiler/BackEnd/SimCodeUtil.mo: function createOdeSystem failed for component torn nonlinear Equationsystem{{{269:161}, {316:337}, {281:162}, {270:160}, {271:163}, {272:174}, {276:165}, {277:132}, {273:164}, {274:122}, {275:121}, {268:128}, {257:48}, {261:63}, {262:33}, {263:32}, {264:61}, {265:44}, {266:310}, {267:311}, {258:30}, {259:313}, {260:312}, {250:8}, {251:5}, {252:4}, {253:7}, {254:6}, {255:314}, {256:324}, {282:187}, {283:184}, {284:183}, {278:186}, {279:185}, {280:308}, {249:227}, {246:242}, {245:212}, {244:211}, {243:240}, {242:223}, {241:304}, {240:305}, {247:209}, {248:307}, {239:306}, {238:297}},
{237:166} Size: 1

Meanwhile, the more complex model, does continue to function.  These errors show up in the  OMEdit Messages Browser, and it happens before the progress window opens.  If I just do check, the model does check correctly. 

If I try to open the debugger, I don't see any equations, likely because these errors happen so early in the simulation build process.
Can anyone offer any hints about what these errors mean?  And how to debug them? 
The strange part is that this model is only slightly different from the older version that ran fine, and the extended version also runs fine.  So, something is wrong with something specific to this model.  But, I'm not sure about how to interpret this error.
FYI, I am running r22854, but I got similar errors when I tried it on 1.9.1beta4.

Any guidance?  Thanks,