stssearch: 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/stssearch - from package: emboss

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

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