icewmbg: 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/icewmbg - from package: icewm

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

On Debian possible default full paths are:

/usr/bin/icewmbg - from package: icewm

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

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