icewmtray: 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/icewmtray - from package: icewm

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

On Debian possible default full paths are:

/usr/bin/icewmtray - from package: icewm

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

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