UDF problem with Parallel Solver
 

I've written a UDF that works perfectly on a "nomal" Fluent solver. Now I just want to lunch my simulation with a Parallel Solver but it arised a small bug with my UDF: I want to write the results of my UDF computation in a txt. file with the command:

fp = fopen("deposit_output.txt","a"); fprintf(fp,"%d\t%.10f\t%.6f\t%.13f\t%.13f\t%.13f\t %.10f\t%.6f\n", n,T_d1,p_d1,m_d1,mf_v,m_d2,T_d2,p_d2); fclose(fp);

But it doesn't work anymore. It doesn't open any txt. file neither write something inside. But otherwise everything works good. Is there a special command to include so that it works on the parallel solver too and writes the results in the txt. file?