hisaxctrl: 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/hisaxctrl - from package: isdn4k-utils

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

On Debian possible default full paths are:

/usr/sbin/hisaxctrl - from package: isdnutils-base

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

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