Thank you @horvathd ,
As far as I remember, I have converted the source.f using the python script and there was no error while building and executing it.
Also, my intention was to sample points as performed in ICRP 144, as was discussed in Biasing in FLUKA - #2 by horvathd, so I tried to divide the sphere in 7 shells and adjusted the sampling (forcing maximum sampling near the cylindrical target) , and since by this the uniformity is lost, I tried to adjust their weights (1 being the outer most shell and then gradually decreasing as it comes closer to the cylinder) . Since this cannot be done using built in cards, I wrote direction sampling and position sampling.
Thanks and regards,
Riya