Need help for install error

Hello，
      When I install Xtail use devtools, it would encounter error like "System command 'Rcmd.exe' failed", and if I install Xtail use install package (xtail_1.1.5-source.tar.gz), it would encounter error  "compilation failed for package Xtail".
      These two questions have been bothering me for many days, could you help me to solve them?
      Thank you very much!