initialization give me a alarm
 

my udf is succsssfuiiy compriled.but when i do the initialization,it will give an alarm :
Error:
FLUENT received fatal signal (ACCESS_VIOLATION)
1. Note exact events leading to error.
2. Save case/data under new name.
3. Exit program and restart to continue.
4. Report error to your distributor.
Error Object: ()

my udf should be right:
#include "udf.h"
DEFINE_PROFILE(currentdensity,thread,position)
{
double potential,icorr,iL,Ecorr,bc,ba;
double a,a1,a2,a3,ic,ia,iA;
face_t f;
icorr=1.53e-5;
Ecorr=-0.55;
bc=0.1;
iL=3.09e-3;
ba=0.1;
begin_f_loop(f,thread)
{
potential=-1*F_T(f,thread);
a1=-1*(potential-Ecorr)/bc;
a2=pow(10,a1);
a=icorr/iL*(1-a2);
ic=icorr*a2/(1-a);
a3=(potential-Ecorr)/ba;
ia=icorr*pow(10,a3);
iA=ic-ia;
F_PROFILE(f,thread,position)=-1*iA;
}
end_f_loop(f,thread)
}

can anyone tell me the possibility of my problem!
thanks!