soundmodemconfig: 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/soundmodemconfig - from package: soundmodem

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