sip-date: 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/sip-date - from package: sofia-sip-bin

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

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