Thanks to sjoelund.se, I've been able to replicate my problem on a reduced model. Here is my model:

model mod1
  parameter Integer n=3;
  Real Z[n, n];
  Real V[n], I[n];
algorithm
  for i in 1:n loop
    Z[i,i] := i^3;
    for k in (i+1):n loop
      Z[i,k] := i * k;
      Z[k,i] := Z[i,k];
    end for;
  end for;
equation
  I = fill(1.0,n);
  V = Z * I;
end mod1;

model mod3
  mod1 mymod;
  Real V2[mymod.n];
equation
  V2 = 2.0 * mymod.V;
end mod3;

"mod1" flattens and simulates fine. "mod3" flattens okay but fails during simulations. The error messages start with the following:

mod3.cpp: In function `int functionDAE_output()':
mod3.cpp:678: error: expected primary-expression before "struct"
mod3.cpp:678: error: expected `)' before "struct"
mod3.cpp:683: error: expected primary-expression before "struct"
mod3.cpp:683: error: expected `)' before "struct"

Here is some of the code the errors point to:

677      tmp41 = get_memory_state();
678      (*struct _array_element_addr(&(*struct _array_element_addr(&$Pmymod$PZ, 2, (modelica_integer)$Pi, (modelica_integer)$Pi)), 2, (modelica_integer)$Pi, (modelica_integer)$Pi)) = ((modelica_real)pow((modelica_real)(modelica_integer)$Pi, (modelica_real)3));
679      tmp38 = (1 + (modelica_integer)$Pi); tmp39 = (1); tmp40 = (modelica_integer)$Pmymod$Pn;
680      {
681        for(modelica_integer $Pk = (1 + (modelica_integer)$Pi); in_range_integer($Pk, tmp38, tmp40); $Pk += tmp39) {
682          tmp37 = get_memory_state();
683          (*struct _array_element_addr(&(*struct _array_element_addr(&$Pmymod$PZ, 2, (modelica_integer)$Pi, (modelica_integer)$Pk)), 2, (modelica_integer)$Pi, (modelica_integer)$Pk)) = ((modelica_real)((modelica_integer)$Pi * (modelica_integer)$Pk));

If I change the algorithm part of mod1 to the following, it simulates correctly.

  Z := {{1,2,3},{4,5,6},{7,8,9}};

I'm on windows XP. These results are on a fairly recently downloaded daily (OpenModelica-revision-6338.msi).

- Tom