II did everything, did double check, but when I submit to verify, the chalenge is wrong: "Challenge Not yet complete... here's what's wrong: 
The initial submission action is not correct for the 'Discount Approval Process'. VP approval does not appear to be required for discounts over 40% for step #2 in the process."

But it's correct, as you can see in diagram:

Hi

 

I have prepared a site http://nbcuni.force.com/commops

My Force.com domain name is nbcuni.force.com

 

I have prepared a robots.txt file (VF page which allows all bots) and uploaded it in Site Robots.txt.

That robots.txt is visible at http://nbcuni.force.com/commops/robots.txt infact it should be visible at http://nbcuni.force.com/robots.txt  (in domain)

 

In Google Webmaster tools the bot crawls at http://nbcuni.force.com/robots.txt and are unable to find the file hence give crawl error (503)

 

How to get Robots.txt at the http://nbcuni.force.com/robots.txt

There are a number of "special" files that must be located in the web root of a public website including:

/robots.txt - Controls web search engine behaviors
/favicon.ico - Icon for website

There doesn't appear to be any way to specify the values for these files. Salesforce has provided a default robots.txt which prevents search engine indexing, but production orgs will need the ability to override this file. Also the location of favicon.ico can be set using meta tags, but the default location is still used by some older browsers, so there should be a way to assign an image to this file. I would hope these two issues could be addressed before production roll out.

George