Here is a bit of information about DLL files. These type of file are Dynamic Link Libraries, available on most Windows based computers. They can be system files pertaining to the Windows operating system, but they are also widely used in applications (Windows programs) as well. So for the common user, a dll file is either a portion of a certain Windows program, or a portion of the operating system itself.

There are two common types of dll files, standard and ActiveX. The difference is in the way they are accessed by the caller application. Standard dll files must be placed at specific locations, where the caller application is actually looking for them. ActiveX dll's can be placed at any location, but they have to be registered before the operating system can make use of them. This is done through the installation process of the application that calls the dll, but there are certain cases when manual registration must be done.

ActiveX dll's can be registered through a system utility named regsvr32.exe that you can find in your System folder, but the best way is to use a dll registration utility, which makes things much easier.

If you want to fix problems with a dll file by copying it from elsewhere, you need to know where it must be placed. Some dll's must be installed in the System folder. Others must be deployed in the application's main installation folder. If you are trying to copy a missing dll onto your computer, and you are not sure where to place it, putting the file in the application folder should be tried first, and then if it doesn't work you can place it in your System folder (this folder is usually something like C:\Windows\System32).

Please note that fixing dll errors by copying is not recommended, especially for the unexperienced user. Such files are provided in a lot of versions and chances are your program will not work due to version mismatch. You need to have specific information about the dll file in order to replace it properly, and even so the replacement may fail. Also - fixing dll errors by copying have a bad impact on your operating system and applications installed, so this would be like the last thing to do in order to fix dll errors your computer may have.