AWStats seems to recognize Google as an external page rather than a
search engine.

As a result, it does not report top search keyphrases and keywords.

Output on the web page:

...
Links from an Internet Search Engine - Full list

Links from an external page (other web sites except search engines) - Full list
- http://www.google.com/url 1,427 1,427
- http://www.google.com/imgres 960 1,025
- http://www.google.com/search 332 367
...

There are no error messages displayed and I did not modify the search_engines.pl library.

Where should I look to find a solution?