@Carl Love 

Thank you for your comment. I learrned from it but the solution for my problem was just making a list of the equations before optimizing that.

setEQs:=[eq1= eq_dP_5, eq2= eq_dmu_5]

fortran(setEQs, optimized)

@Carl Love 

Hi,

I have already a FORTRAN code solveing my complicated ODEs numerically. The only thing that I need is that translating my equations calculated in Maple to  "optimized" Fortran.  My problem is only with optimization of several equations that Maple doesn't rememeber that it has used some names before. This makes errors!