The problem you are facing is a bit general so I will need some additional information in order to resolve it. Can you please send me a screenshot of the full content of the Firebug error and a copy of the Error log file located in App_Data/Sitefinity/Logs folder. Apparently some assembly fails to be located but based on the information given I cannot conclude which one.
For the moment I can recommend re-installing the news module and see if this fixes the problem. Additional information that can be helpful for you is located in this forum thread.