[Koha] fine calculation not working

Hi, I am working on koha on win XP, In my system everything working correctly but when a book not return on time then it shows only overdue item with no. of days and fine shows 0 always, I have try many option and also find everywhere but still I am failed to solve that problem, So please anybody give me solution for that. with complete step and also screenshot if possible. thanks -- *Regards, kamlesh kumar shukla S/W Developer, Delnet, Vasant Kunj, New Delhi. (next to paschimabad gate of JNU), 9911962290, 26741232 (Ext. : 309)*