sockdebug: 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:

/usr/sbin/sockdebug - from package: ndoutils-common

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