cvm-testclient: 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
/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/cvm-testclient - from package: cvm

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