Bilal,
Thanks for your reply. I actually figured out the answer to this. You don't necessarily have to have administrative privileges, but the folder where you are copying your ocx/dll file needs to allow all the users to have Full Control. For example, if you want to copy and register cwui.ocx under %windir%\system32 folder then you need to go to the Properties for System32 folder and give Everyone permissions to have Full Control on that folder. Once you have registerd the file, you may set the Permissions back to its original value. Anyway, you may already know this. Thanks for your reply.
Nish