I am using sitefinity 8.2 trial version for the POC of my running website. It is configured in my local development box. I added the custom site master page in the pagetemplate section and and its related files into the file system of configured site. When I try to view my custom master page it is throwing "The Controls collection cannot be modified because the control contains code blocks (i.e. <% ... %>)." error. My master page contains script block, child controls and it is inherited from the root master page. The root master page finally inherits the basepage. Even I tried to put the script in the div/placeholder container is not solving the problem.
I have attached the screenshot for reference. Please advise me how to proceed on this.