FBML Error (line 11): illegal tag “body” under “fb:tab-position”

Errors while loading page from application
Parse errors:
FBML Error (line 11): illegal tag “body” under “fb:tab-position”

If you are using IIS, you may see the above message when you add a tab to your facebook page. It is because IIS doesn’t allow POST requests to html files by default.

Solution 1: Configure your IIS to accept POST requests to html files

Solution 2: Change your .html into .php