Koha error

The following fatal error has occurred:

Can't call method "leader" on an undefined value at /usr/local/koha/opac/cgi-bin/opac/opac-MARCdetail.pl line 103.
Apache
Koha 3.00.02.012
Koha DB 3.0004020
MySQL mysql Ver 14.14 Distrib 5.1.37, for pc-solaris2.11 (i386) using readline 5.1
OS SunOS catalogue 5.11 11.0 i86pc
Perl 5.010001