The XCEEDZIP.DLL file is an ActiveX component, but can also be used by direct DLL calls through the use of its exported API.

When you use the XCEEDZIP.DLL file as a DLL instead of an ActiveX component, it doesn't need to be "registered" on the system (by running REGSVR32.EXE for example) – it works in the same manner as regular 32-bit DLLs do. However, we recommend that you register the DLL anyway if possible, in order to ensure that any existing applications on that machine do not run into problems.

For a 32-bit application that uses the Xceed Zip v5.0 through direct DLL API calls, the XCEEDZIP.DLL must be available on the user's system. The directories searched to find the DLL are, in order: the directory from which the application using the DLL is loaded, the current directory, the Windows System directory (named SYSTEM32 under Windows NT), the 16-bit Windows System directory (Windows NT only), and finally, the directories listed in the PATH environment variable. We recommend that you place the XCEEDZIP.DLL in the user's Windows System directory (C:\WINDOWS\SYSTEM).

Make sure that you aren't overwriting a newer version of the DLL when you place it there. To help you determine the version number of the DLL, a version information resource has been embedded into it. When installing or upgrading your applications, you may refer to this information to insure that the latest DLL is being installed. To view the version information, check the file properties. With Windows Explorer, press ALT-ENTER on a file to get the version information. Many of the better installation or setup programs automatically know how to access version information resources.