Flat rate is common in broadband access to the Internet in the USA and many other countries. A charge tariff is a class of linear rate, different from the flat rate, where the user is charged by the uploads and downloads (data transfers).
MUI stands for Multilingual User Interface and .dll.mui files are simply libraries(Dlls) that contain resources dedicated to localization : for an application to support multiple languages,dlls containing specific resources must be available eg language resources(arabic,french,english,chinese....
The aclayers.dll is a kind of Windows Compatibility DLL. This file is created by Microsoft Corporation and is an integral part of WindowsÂ® Operating System. It is a hidden system file and is usually located in the %SYSTEM% sub-folder. The normal size is 451,072 bytes.