[Koha] error with rebuild_zebra.pl

I am using last version of koha3, when I import a file with records in UNIMARC format using "bulkmarcimport.pl" all is ok, but when I reindex zebra using "rebuild_zebra.pl" I get this error: "problem with :4683 : Entity: line 36: parser error : Extra content at the end of the document" I have in my file 34000 records and zebra just index 6520, and show this error [warm] Record didn't contain match fields in (bib1,Local-number) zebraidx(4478) [log] error grs.marcxml.record /tmp/W7d3aYhZuR/biblio/exported_records 6159525 how can I fix this in order to zebra index all records without problems. thanks.