sipquery: 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/sipquery - from package: sipwitch

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

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