Do you have any previous versions of Digital File Pro or Universal Email installed? If so you will need to make sure that they are uninstalled before using the new UE4.
It sounds like you may have a problem with the cache file or a corrupt configuration folder. Here are the steps you can take to overcome these issues.
Delete cache file
After you have gone through the steps here for these make sure to remove any of the remaining extensions, then try installing UE4 again and test it out. If you encounter any further problems, especially js errors make sure to post back with the full and exact error you are getting.