[Koha] Can't call method "as_usmarc" on an undefined value at /usr/share/koha/lib/C4/Search.pm koha

[Priyadarsan kp]

I use koha 	3.02.03.000 on ubuntu 10.10
I exported the biblios using marc export tool
when i search catelogue some times i get the error Can't call method
"as_usmarc" on an undefined value at /usr/share/koha/lib/C4/Search.pm
koha
I am using nozebra.

-- 
Priyadarsan K. P.
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Lecturer in Mathematics,
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