I frequently use the two opensource applications referred to in the title & also frequently forget how to get them working properly. I tackled logrotate first with a little help from here: http://teklimbu.wordpress.com/2007/10/16/managing-your-linuxunix-log-files-using-logrotate/
What I always forget is to setup the file structure:
mkdir -p /usr/local/etc/logrotate.d
mkdir /var/lib/
touch /var/lib/logrotate.status
and to do the first run:
/usr/local/sbin/logrotate -d /usr/local/etc/logrotate.conf/usr/local/sbin/logrotate -f /usr/local/etc/logrotate.conf
Using Virtualmin the configs should be setup automatically but without these options first it just fails to run.
Onto Webalizer. The main problem I run into is the DNS resolving. Setting the DNSCache & DNSChildren covered in DNS.README isn't enough if the db isn't writable. Make sure to check that otherwise it will complete successfully but not give any useful IP info.