Ax2012 EP error: The 'Metadata' property is read-only and cannot be set.

Solution:
1. Open the web control in Visual studio
2. Open the Design file of the web control (.ascx)
3. Click source button to view Ascx coding (HTML code)
4. Find(ctrl + F ) Metadata in the ascx code
5. Simply delete the word whereever it is appear in ascx file
6. Save and deploy the webcontrol.
7. Open the webpage again, the error is resolved.