If the "Rob Papen" instrument does not show up inside Cubase SX. (PC)

Answer:
This happens because of the faulty "VSTplugins" location that occurs if you use also other Steinberg products like Wavelab.
CubaseSX has also a own "Vstplugins" folder called: Programs/Steinberg/Cubase 4/Vstplugns

A way to solve this, without installing again our software:

Cubase SX (Startup the program.).
1. Select: "Devices" and then "Plug-in" information
2. Select: VSTplugins
3. Select: VSTplugins "path".
Add "manual" the location in where products are installed.
Most of the time Programs/Steinberg/Vstplugins needs to be added as well.

Other option is to run the installer again and pick the right location.
Close at the end of the install "Syncrosoft" if that pop-ups, because the license is already active.