It think it fails because it wants to save the binary to /gnu/store where the package "r-minimal" is installed.

It might be also that r-minimal has to be installed with "

"--enable-R-shlib"

In gn/packages/statistics.scm there is "r-with-tests". Unfortunately it is not a public package, so I cannot install it easily

RServ is quite important: any interop with R (on multiple languages) goes via this socket-server.