The write-operations of rar/7z archives require an external packer.
In settings->compressor you can find the 7z and rar default parameters and external packer names. They are listed there without any path assignment assuming that winrar.exe and 7z.exe are already available through your set %PATH% environment variable.

So either adjust the path there or be sure the executables are available in your Windows %PATH% environment.


Roman Scherzer