aakk9999 - 11:50 pm on Jul 28, 2013 (gmt 0)
You have a few things wrong with your robots.txt:
a) "Dissalow" is misspelled, it should be "Disallow"
b) If you have "Disallow: /" then you are blocking the whole site from crawling. In this case Google will drop you in a matter of days. You need to disallow a specific URL pattern in order to stop Google crawling your duplicate pages
c) "Noindex: /" is not a valid robots.txt directive. To noindex a page, you must use robots meta tag on the page itself <meta name="robots" content="noindex">, but in this case you need to let Google crawl the page in order to see this meta tag
As far as I know, Joomla is commonly hosted on Apache server and Apache uses .htaccess You can edit .htaccess to set up 404 or 410 response codes or to set up a 301 redirect to a correct URL. I also seem to remember that there are some Joomla plugins for SEO friendly URLs and if set up correctly, it will not expose Joomla internal dynamic URLs, so perhaps you should investigate whether you could use this.
Concerning the 404 error I don't think it is possible create a 404 error in joomla , is it ? because joomla works in such a way that with an article ID you can create 1000 of address
Has the article appeared in the wrong section of your website just because you upgraded Joomla or because of some other changes?
The additional URLs point to existing page that is true but with the wrong parameters ( For example I have an article that appears under the wrong section of my website and it created and new URL )
Have you looked into using canonical link element for your article, where you define what should be your canonical (main) URL for an article? You may want to search for Joomla canonical plugin and investigate whether using it would solve your multiple URL problems.
I would however suggest that you do these changes on a test site (which is blocked from Google via robots.txt or via password access) and only when you are happy with results, to port these changes to your live site, otherwise you may do further damage to your site.