tar: command not found

Have You tried accessing the binary with the full path?

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:

/bin/tar - from package: tar

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

On Debian possible default full paths are:

/bin/tar - from package: tar

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