In my Google webmaster tools there are some not found crawl errors which are strange. The URLs comes from a site that shows top domain listing for input keywords(can't write the site name here since it will be removed by moderator). But these URL don't exists in my site, the strangest of them all is a URL that points to a php page, i have a asp.net site and no php page.It is certain that google crawler will not find these URLs since they never exists but why that site (reputable one) is linking wrong URLs.
Is this a matter of concern or i can avoid these not found errors ?