Could be your country isn't allowed. Can't imagine why.
I wouldn't depend on that FAQ. It doesn't seem to be honest about things.... ie... I have purchased from people in other countries and have sold to people in other countries.
Only merchants with a U.S. or U.K. business address and bank account can sign up for a Google Checkout account to accept payments for physical goods, services, and digital goods on 3rd party websites. We look forward to expanding our service's availability in the future, although we're unable to comment on specific timelines.
Buyers located in countries across the world can sign up for Google Wallet accounts to make purchases across the web with a single username and password. To review a list of supported countries for buyers, please check the 'Location' drop-down menu on the sign up page at https://www.google.com/accounts/NewAccount?service=sierra&signup.
I read the letter, but it still doesn't make sense. As I said, I know people who sell from other countries and they're not just using Google Play to sell Android Apps.
..... Go figure .... Sorry you're not having any luck