icecast2: 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/icecast2 - from package: icecast2

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

Error in other languages:
icecast2: bevel nie gevind nie
icecast2: comandă negăsită
icecast2: comando não encontrado
icecast2: commande introuvable
icecast2: command not found
icecast2: käsku ei ole
icecast2: không tìm thấy lệnh
icecast2: komanda nerasta
icecast2: Kommando nicht gefunden.
icecast2: kommandot finns inte
icecast2: komut yok
icecast2: nie znaleziono polecenia
icecast2: níor aimsíodh an t-ordú
icecast2: no se encontró la orden
icecast2: no s'ha trobat l'ordre
icecast2: opdracht niet gevonden
icecast2: parancs nem található
icecast2: perintah tidak ditemukan
icecast2: príkaz nenájdený
icecast2: příkaz nenalezen
icecast2: команда не найдена
icecast2: командата не е открита
icecast2: 命令找不到
icecast2: コマンドが見つかりません