ipcheck: 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/sbin/ipcheck - from package: ipcheck

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

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