Hi
please never put your whole error here,
now check your data in these statements, where it is giving errors in line no 1402, please check for any arithmatic error , like error in conversion etc, see that the value of tunehd64-avail_size has any value 0, which might cause any error.
if tunehd64-avail_size ne 0.
free_size_p = free_size * 100 / tunehd64-avail_size.
else.