Having a massive amount of duplicate crawl errors

[stanken]

Im having over 400 crawl errors over duplicate content looking like this: http://www.mydomain.com/index.php?task=login&prevpage=http%3A%2F%2Fwww.mydomain.com%2Ftag%2Fmahjon http://www.mydomain.com/index.php?task=login&prevpage=http%3A%2F%2Fwww.mydomain.com%2Findex.php%3F etc.. etc... So there seems to be something with my login script that is not working, Anyone knows how to fix this? Thanks

[Cyrus-Shepard]

There isn't necessarily anything wrong with your login, it looks like it's  carrying a referring parameter in the URL so that it knows where to send you next. Not the most sophisticated way to do it, but very common.

Since it returns a 404 the easiest solution would be to make your login link/button "nofollow". You could add this to the html or javascript fairly easily.

Or you could place a directive in your robots.txt file disallowing these urls, Something like:

User-agent: *
Disallow: *login

should do the trick. (but test this)

If this is a javascript code causing this, you might try wrapping the script in CDATA tags. This might also do the trick.

Hope this helps. Best of luck with your SEO!