iscsistart: 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:

/sbin/iscsistart - from package: iscsi-initiator-utils

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

On Debian possible default full paths are:

/usr/sbin/iscsistart - from package: open-iscsi

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

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