qsstv: 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 CentOS possible default full paths are:

/usr/bin/qsstv - from package: qsstv

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/qsstv - from package: qsstv

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

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