RegSvr32 is the Windows utility for registering ActiveX/COM controls such as DicomObjects.

Normally, if RegSvr32 is used to register an OCX, then any previous registration locations of the same object (as identified by internal GUIDs) will be over-ridden, but there is a large bug in this system, such that if DicomObjects (or any other OCX) has been registered as part of an InstallShield instllation, then the copy installed as part of that process (normally in Windows\System32) cannot be changed simply by using regsvr32 on another copy. The annoying thing is though that regsvr32 appears to work, but simply does not.

There are 2 solutions:

1. Uninstall the Application which included DicomObjects
2. Delete the copy in Windows\System32 before registering elsewhere