This can happen when the functionality was turned off during deployment installation.
As an administrator click Windows Start and type regedit:
Copy and paste this path in the registry editor: HKEY_LOCAL_MACHINE\SOFTWARE\Autodesk\Inventor\RegistryVersion24.0
Select EnableCollaboration, right click and select Modify.
Change the value to 1 and select Ok.
Restart Inventor and you should have the ability to enable shared views.