diff --git a/src/fortran/nonlinear_poisson_equation.F90 b/src/fortran/nonlinear_poisson_equation.F90
index 57f67e1..414efeb 100644
--- a/src/fortran/nonlinear_poisson_equation.F90
+++ b/src/fortran/nonlinear_poisson_equation.F90
@@ -142,8 +142,8 @@ PROGRAM NONLINEAR_POISSON_EQUATION
   CALL cmfe_OutputSetOn("nonlinear_poisson_equation",Err)
 
   !Get the computational nodes information
-  CALL cmfe_ComputationalNumberOfNodesGet(NumberOfComputationalNodes,Err)
-  CALL cmfe_ComputationalNodeNumberGet(ComputationalNodeNumber,Err)
+  CALL cmfe_ComputationalNumberOfNodesGet(numberOfComputationalNodes,err)
+  CALL cmfe_ComputationalNodeNumberGet(computationalNodeNumber,err)
 
   !-----------------------------------------------------------------------------------------------------------
   ! COORDINATE SYSTEM