icon_append_index: 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 Debian possible default full paths are:

/usr/bin/icon_append_index - from package: ctn

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

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