Quote:
Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately.
Parser Error Message: Only Content controls are allowed directly in a content page that contains Content controls.
From the error, it is clear that you are only allowed to place controls inside content page.
But you have also included the html, body, form tags, which are also there in Master Page.
So, when the page executes it finds these tags two times one in Master page and another in Content page, which is the problem.
Only define the controls inside the Content page, and make sure you don't repeat the tags in Content page.
Thanks...