icecast: 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 CentOS possible default full paths are:

/usr/bin/icecast - from package: icecast

You may install the required package with command yum install {package}

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