advdef: 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/bin/advdef - from package: advancecomp

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