A few things to check:
Was Dreamweaver closed when you copies the WAUniversalEmail.xml file over? you should close Dreamweaver before copying that file to the configuration folder.
Try deleting the Dreamweaver Cache file from the user configuration folder, more details can be found here:
If you are still having problems, what is your OS and Dreamweaver Version?
What is the full path to the folder you are copying the WAUniversalEmail.xml file to?