A good starting point to analyze the problem reasons is to switch debug on:
I suspect it will output to server’s log traces of attempts to load
which is obviously incorrect. In order to let PD4ML interpret /broker-module/BL.css as a web path you would need to pass either the servlet context or HTTP request object to PD4ML. It could be done with the following API calls.
useHttpRequest(HttpServletRequest httpRequest, HttpServletResponse httpResponse)[/language:1w9ymuy5]