[Koha] Software error at the time of checkin

Dear friends I got software error at the time of checkin Can't call method "truncate" on an undefined value at /usr/share/koha/lib/C4/Circulation.pm line 1966 For help, please send mail to the webmaster ([no address given]), giving this error message and the time and date of the error. KINDLY HELP ME TO SOLVE THE ERROR -- Sahadeo D. Taware Librarian, M.L.I.Sc., NET Thakur College of Science and Commerce Thakur Village, Kandivli(E), Mumbai 400101 Mob. No 9324912816 Office 28870627 Extn. 126