Google webmaster tools found 1000s of 404 page not found
I have got one issue on three websites where Google Webmaster tools found 1000s of "404 page not found" but I don't know how come he is searching those pages. For instance I am getting crawl errors for http://www.topvalais.ch/ZdRbW/Rubriques.aspx or http://www.topvalais.ch/RcjeO/ZYmXX/Rubriques.aspx or http://www.topvalais.ch/STXTP/OhbOX/Rubriques.aspx or http://www.topvalais.ch/PddjP/KWPjO/...Rubriques.aspx etc... All those pages do not exist. The real existing page is http://www.topvalais.ch/Rubriques.aspx
Where does Google Crawler's find those URLs with garbage's characters ? Has it something to do with the URL Rewriting thing ?
And when looking at referrer again it's something I wouldn't know where Google's crawler found them. See details here: http://www.corobori.com/sos/picTopVS.jpg
Any clue welcome !