in.rexecd: 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/sbin/in.rexecd - from package: rsh-server

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

On Debian possible default full paths are:

/usr/sbin/in.rexecd - from package: rsh-server

You may install the required package with command apt-get install {package}

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