xsec-xtest: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/xsec-xtest - from package: xml-security-c-utils

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