CSS Menu Writer is definitely compatible with your environment and DW version. Is it possible that you have the preview disabled? You can check on this under Edit > WebAssist Preferences, in here select preview from the left and check it's status. If it is disabled here then you will not see the preview in the interface.
As for the code that is being produced on the pages can you post back with a page in a zip file for us to see? Does the menu function for you when you view it?