1) The graphs really need units of measurement, either next to each value or at least in a legend. For example, pie charts with percentages just say "95" and "5". But it is not obvious that those are percentages--they could just be the count of hits for that report.

2) Invalid pages should really have the HTTP Referrer field displayed with them. Most invalid pages are bad links from external sites and source, or misspellings by users. But, if it is from within the site and is a broken link, how can you tell which page it came from? If you added the Referrer field it would cover both cases.