All I can say is, I wrote the instructions exactly as I did it.
The webanalyser folder should be in the same place as your MODx assets and manager folders.
The snippet code should be
require("webanalyse/include/stats_main.inc");
$stats = new init(true, 'webanalyse/');
Then in your main MODx template, put the snippet tag just before the last </body></html> tags.
To see your stats, go to yoursite.com/webanalyse