rcs-checkin: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/rcs-checkin - from package: emacs-common

You may install the required package with command yum install {package}

Error in other languages:
rcs-checkin: bevel nie gevind nie
rcs-checkin: comandă negăsită
rcs-checkin: comando não encontrado
rcs-checkin: commande introuvable
rcs-checkin: command not found
rcs-checkin: käsku ei ole
rcs-checkin: không tìm thấy lệnh
rcs-checkin: komanda nerasta
rcs-checkin: Kommando nicht gefunden.
rcs-checkin: kommandot finns inte
rcs-checkin: komut yok
rcs-checkin: nie znaleziono polecenia
rcs-checkin: níor aimsíodh an t-ordú
rcs-checkin: no se encontró la orden
rcs-checkin: no s'ha trobat l'ordre
rcs-checkin: opdracht niet gevonden
rcs-checkin: parancs nem található
rcs-checkin: perintah tidak ditemukan
rcs-checkin: príkaz nenájdený
rcs-checkin: příkaz nenalezen
rcs-checkin: команда не найдена
rcs-checkin: командата не е открита
rcs-checkin: 命令找不到
rcs-checkin: コマンドが見つかりません