sudo apt-get install awstats

Ubuntu.com AWStats

Copy this in “/etc/logrotate.d/awstats

/var/log/apache2/*_log {
    weekly
    missingok
    rotate 52
    compress
    delaycompress
    notifempty
    create 644 root root
    sharedscripts
prerotate
        /usr/local/awstats/tools/awstats_updateall.pl now > /dev/null
endscript
postrotate
        /etc/init.d/apache2 reload > /dev/null
endscript
}

The list of refs and OS info is empty because of a wrong perl version. Error occurs with perl above 5.10.0.
Check your version with:

perl -v

Perl changed some things which mess up the awstats perl file

Open your awstats.pl

vi /usr/local/awstats/wwwroot/cgi-bin/awstats.pl

if (/\(\?[-\w]*:(.*)\)/) { $1 }

OptimizeArray {
my $array = shift;
my @arrayunreg = map { UnCompileRegex($_) } @$array;
my $notcasesensitive = shift;

Line 7812, comment

shift =~ /(\?[-\w]:(.))/;

UnCompileRegex {
shift =~ /(\?[-^\w]:(.))/;
return $1;
}