Awstats Problem

Hello,

I am using Webmin and Virtualmin on my VPS. And I have problem awstats. I set awstats to require password on virtualmin server settings. When I enter the page "http://domain/awstats/awstats.pl" it asks for password but when I enter, it diverts me to page with error "500 Internal Server Error". Entering page "http://domain/awstats" also doesn't work, it says "403 Forbidden". The only solution to see awstats reports is to enter "https://domain/awstats/awstats.pl", and it shows the report without requiring password. Is this a bug?