[Koha] C4::AUTH problem

[zuxiaolong]

     When I type http://localhost/cgi-bin/koha/opac-main.pl in browser, I
     got message below:
Internal Server Error
The server encountered an internal error or misconfiguration and was
unable to complete your request.
Please contact the server administrator, aa at 163.com and inform them of
the time the error occurred, and anything you might have done that may
have caused the error.
More information about this error may be available in the server error
log.
Apache/2.0.47 (Unix) DAV/2 Server at localhost Port 80

     Then I run command : perl opac-main.pl, I got message below:
Can't locate C4/Auth.pm in @INC (@INC contains:
/vservers/ireta/Library/cgi-bin/koha/C4 /usr/lib/perl5/5.8.1/i686-linux
/usr/lib/perl5/5.8.1 /usr/lib/perl5/site_perl/5.8.1/i686-linux .........
>BEGIN failed--compilation aborted at /vservers/ireta/Library/cgi-bin/opac/opac-main.pl line 7.


My environment is like this: Debian(sid) koha2.0pre4   perl(5.8  updated
from 5.6)  apache2.0.47(compiled)  Modules(installed before updated in
woody), Mysql

So what can I do to resolve it? 
Thanks.
-- 
  zuxiaolong
  hugojoe at fastmail.fm

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