That seems to suggest an incorrect version of one or more required components is installed, which is in turn preventing the server package from being installed.
I would suggest sharing the package file so that it can be used to help determine the cause of the problem by attempting to install it manually.
With the old UI and launcher this issue would be fairly easy to diagnose; when trying to manually install the package through the 'Content Manager' any required components that are "missing" can be identified by hovering over the package with the mouse cursor.
If the new UI is being used then there may be some way of seeing, from within the game, which components are missing when trying to manually install the package,
Oh! It is here!
New UI - Main Meny - Content - Packages
You get the message of what you are missing when trying to install it from here! AFAIK the rfmod should be here so it is possible to check.