Error: Plugin load for plugin 'hostinfo' failed with return code: Error: Can't locate Net/XWhois.pm in @INC (@INC contains: /usr/local/lib64/perl5 /usr/local/share/perl5 /usr/lib64/perl5/vendor_perl /usr/share/perl5/vendor_perl /usr/lib64/perl5 /usr/share/perl5 . /www/htdocs/cgi-bin/lib /www/htdocs/cgi-bin/plugins /www/htdocs/cgi-bin/plugins) at (eval 7) line 1.

Setup ('/www/htdocs/cgi-bin/awstats.buildarch.com.conf' file, web server or permissions) may be wrong.
Check config file, permissions and AWStats documentation (in 'docs' directory).