zkCleanup.sh: 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

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 Debian possible default full paths are:

/usr/share/zookeeper/bin/zkCleanup.sh - from package: zookeeper

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