Installing the 64 bit 1.82d update for RMX, in Cubase 5, PC, Win 7 can easily go wrong and lead to confusion.
With the help of Tech support (my thanks) I have solved the issues and thought I would post here if anyone needs it.

In summary, you need to achieve the following:

a] Install a 64 dll in the correct directory

b] Install a shortcut to sage in the Spectrasonics directoy

c] Ensure the shortcut is pointing to the correct folder.

D] Ensure that Devices\Plugin information, in Cubase, is searching in the correct Directory for your plugin. Note: If you mistakely have more than one dll in a Plugin Path (maybe you didn't delete an old one?) then Cubase instrument panel will only display one dll - maybe the wrong one. See below.

Here is a fail safe procedure:

1. Remove all StylusRMX dlls on hard drive (search first) * some can be in obscure directories so do a search of all drives.
2. If SAGE is in a custom location (Not C: Program folders\Spectrasonics) Remove all shortcuts to SAGE on C drive.
4. Selecting to install only a 64 bit dll, install the 1.82d update. Take careful note of the location you select for the 64 bit dll to go to (for some reason the installer wants to put it in a Cakewalk directory - even though you might not have Cakewalk) You can override this during install.
5. Search for the dlls again (You should only have one - but check) - delete any unnecessary dlls the installer might create leaving only one 64bit dll in C: Program folders\Spectrasonics
6. Search for again any SAGE shortcuts created by the installer - delete.
7. Create a shortcut to your (should be only) SAGE Folder rename it SAGE (not SAGE Shortcut)
8. Place this in C: Program Folders\Spectrasonics
9. Start Cubase - go to Devices/Plugin information, ensure the path to your Spectrasonics folder is included in the Plugin Paths - add if necessary by clicking the button 'VST 2xPlugin paths'. Update the two update buttons either side of this button.
10. By this stage everything should work. If you want you can check the floppy disk icon in the RH corner of the RMX GUI to ensure you have the correct update installed - bottom of the pop up list.

Note: if you install incorrectly, or abandon a part install, this can install incorrect short cuts and dlls which can create HAVOC Foir instance Your RMX GUI might not find the correct SAGE Folder, It may be the wrong dll creating the Cubase GUI, the SAGE shortcut could potentially point to a redundant SAGE folder hidden away on your hard drive - there are a lot of unpleasant possibilities.

Dont forget if you are running win 7 64 bit (and vista 64?) then you will have tow program folders - one named 'x86'. If you install the 32 bit and the 64 bit updates (which can be done). Make sure that the appropriate shortcuts and dlls are set up correctly.

Following the above procedure should eliminate this