Finally I get a solution to my missing get_aspx_ver.aspx 404 and alert email:
"VS.NET looks for this file if it needs to determine what version of the framework you’re using. Since it doesn’t care about the contents of the page, it just looks in the headers and ignores the Internal 500 message. — The file doesn’t exist, but VS has to call *something* to get a response header."
"It’s not actually a problem, it’s “supposed to work that way”. Heh whatever. It’s still a pain. Suggested workarounds from Microsoft include changing your error handler to ignore calls to the file or to just create an empty one."