Fail to simulate a simple model

[audrey.jardin@…]

The following model reports the error message

"Translation 12:17:44 0:0-0:0 Internal error Transformation Module PFPlusExt index Reduction Method Pantelites failed!
Translation 12:17:44 0:0-0:0 Internal error Optimisation Module removeSimpleEquations failed.
Translation 12:17:44 0:0-0:0 Internal error Circular Equalities Detected"

while it simulates well in Dymola.

model ExtractionSetSTest_WithoutUncertainties
  Real x1;
  Real x2;
  Real x3;
  Real y1;
  Real y2;
  Real y3;
equation 
  x1+x2 = 0;
  x1-x2 = 0;
  y1 = x2+2*x3;
  x3-y1+y2=x2;
  y2+y3=0;
  y2-2*y3=3;
end ExtractionSetSTest_WithoutUncertainties;