[Koha] software error

Respected all I am facing the following error, in circulation module., but if we refresh the page after this error comes then circulation works perfectly. Software error: Can't call method "subfield" on an undefined value at /usr/share/koha/lib/C4/Biblio.pm line 2965. -- Thanks and Regards Sandeep Bhavsar Librarian Dr.V.N.Bedekar Institute of Management Studies Thane(W) 400601 MUMBAI. INDIA @@@@@@@@@@@@@@@@@@@@@@@@@@ email : sandeep.bhavsar@gmail.com Mob : 9029 345777 elibrary :http://www.vpmthane.org/im/elib/main.htm @@@@@@@@@@@@@@@@@@@@@@@@@@