[Koha] Error: Can't call method "append_fields"

Goods, I've been istalled Koha 3.0.0 and all times I try to catalog, this error message appears: Can't call method "append_fields" on an undefined value at /usr/local/share/perl/5.10.1/MARC/File/SAX.pm line 92. Apache Server version: Apache/2.2.14 (Ubuntu) Server built: Apr 13 2010 19:28:27 Koha 3.00.00.107 Koha DB 3.0000107 MySQL mysql Ver 14.14 Distrib 5.1.41, for debian-linux-gnu (i486) using readline 6.1 OS Linux koha 2.6.32-24-generic #38-Ubuntu SMP Mon Jul 5 09:22:14 UTC 2010 i686 GNU/Linux Perl 5.010001 Someone could help me? What should I do to catalog? -- Geovana de Paula Santos Tarricone