icewmbg-experimental: 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/icewmbg-experimental - from package: icewm-experimental

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