mab2_convert: 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 Debian possible default full paths are:

/usr/bin/mab2_convert - from package: libcatmandu-mab2-perl

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

Error in other languages:
mab2_convert: bevel nie gevind nie
mab2_convert: comandă negăsită
mab2_convert: comando não encontrado
mab2_convert: commande introuvable
mab2_convert: command not found
mab2_convert: käsku ei ole
mab2_convert: không tìm thấy lệnh
mab2_convert: komanda nerasta
mab2_convert: Kommando nicht gefunden.
mab2_convert: kommandot finns inte
mab2_convert: komut yok
mab2_convert: nie znaleziono polecenia
mab2_convert: níor aimsíodh an t-ordú
mab2_convert: no se encontró la orden
mab2_convert: no s'ha trobat l'ordre
mab2_convert: opdracht niet gevonden
mab2_convert: parancs nem található
mab2_convert: perintah tidak ditemukan
mab2_convert: príkaz nenájdený
mab2_convert: příkaz nenalezen
mab2_convert: команда не найдена
mab2_convert: командата не е открита
mab2_convert: 命令找不到
mab2_convert: コマンドが見つかりません