There seems to be a new policy about allowing a program access to the registry on a client machine that some Antivirus companies take a harder stance on.
The "PUA" signature means "potentially unwanted application" and is a very low risk detection they set on everything they are not 100% sure about, until they have had a chance to do a more thorough analysis. We are currently working with antivirus companies to make sure that this detection is cleared as soon as possible.
In the meantime I can assure you that using the DLL-files Fixer is completely safe and to reinstall, simply "accept" it through your ntivirus, and add it to a whitelist/exclusion in the security settings. In some cases, you add the entire program folder, in some cases, just the main “dllfixer.exe” and “dffsetup.exe” files themselves. You can find the files in:
C:\Program Files (x86)\Dll-Files.com Fixer\ and