Hi @Georgina Naylor
Since IBM SPSS Statistics 28.0.0.0 was released, the product ships with its own instance of R. IBM SPSS Statistics versions and R versions are very specific to one another. You can't mix and Match.
If you are installing IBM SPSS Statistics 28.0.0.0 or later, there is no other installation that needs to be done (with the exception of XQuartz on macOS). Statistics and R should run together right out of the box. If at some point you need to install an R related SPSS Statistics Extension command, these are available from the Extension Hub withint the client interface and the installer will seek out and install dependencies.
Your errors above seem like a corrupted installation. I would begin with a clean re-install of IBM SPSS Statistics (28.0 or later, current version is 31.0.0.0) and then test your R instance from there. If that works, then begin installing Extension Commands as needed.