icewm: 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/icewm - from package: icewm

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

On Debian possible default full paths are:

/usr/bin/icewm - from package: icewm

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

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