testhost: 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/testhost - from package: suck

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