Your INF file should have something like this; [Add.Code] dbclient.dll=dbclient.dll

[dbclient.dll] file=http://yoursite.com/dbclient.cab clsid={9E8D2F8 -59 C- D0-BF52-0020AF32BD64} RegisterServer=yes FileVersion=4,0,0,36

Replace "yoursite" with your HTTP address where the cab file resides. FileVersion is the version of the file in your CAB file (check the version information of DBCLIENT to make sure the above matches). Make sure FileVersion is the version of your DBCLIENT.DLL. You can put dbclient.dll in a cab file using CABARC found in the delphi\bin directory. A sample CABARC command line might look like the following example. CABARC N DBCLIENT.CAB DBCLIENT.DLL