bzdiff: 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/bzdiff - from package: bzip2

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

On Debian possible default full paths are:

/bin/bzdiff - from package: bzip2

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

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