[Koha] CDS/ISIS to Marc conversion issue

Hi, We have our library running on CDS/ISIS database. I use the bulkimport.pl script for loading into the mysql. Most of the fields get loaded into the database except for the barcode (accession #). Can someone let me know the possible reason for it. Can it be due to multiple values for the field? If so, please let me know how to resolve it since I've tried most of the attempts in the marc_subfield_structure table. Please let me know if some more information is required. Thanks, Sai Bhalaji Sri Sathya Sai University.