ocfs2_hb_ctl: 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 Debian possible default full paths are:

/sbin/ocfs2_hb_ctl - from package: ocfs2-tools

You may install the required package with command apt-get install {package}
Error in other languages:
ocfs2_hb_ctl: bevel nie gevind nie
ocfs2_hb_ctl: comandă negăsită
ocfs2_hb_ctl: comando não encontrado
ocfs2_hb_ctl: commande introuvable
ocfs2_hb_ctl: command not found
ocfs2_hb_ctl: käsku ei ole
ocfs2_hb_ctl: không tìm thấy lệnh
ocfs2_hb_ctl: komanda nerasta
ocfs2_hb_ctl: Kommando nicht gefunden.
ocfs2_hb_ctl: kommandot finns inte
ocfs2_hb_ctl: komut yok
ocfs2_hb_ctl: nie znaleziono polecenia
ocfs2_hb_ctl: níor aimsíodh an t-ordú
ocfs2_hb_ctl: no se encontró la orden
ocfs2_hb_ctl: no s'ha trobat l'ordre
ocfs2_hb_ctl: opdracht niet gevonden
ocfs2_hb_ctl: parancs nem található
ocfs2_hb_ctl: perintah tidak ditemukan
ocfs2_hb_ctl: príkaz nenájdený
ocfs2_hb_ctl: příkaz nenalezen
ocfs2_hb_ctl: команда не найдена
ocfs2_hb_ctl: командата не е открита
ocfs2_hb_ctl: 命令找不到
ocfs2_hb_ctl: コマンドが見つかりません