iksroster: 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/iksroster - from package: iksemel-utils

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

On Debian possible default full paths are:

/usr/bin/iksroster - from package: libiksemel-utils

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

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