stg-swallow: 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/stg-swallow - from package: stgit-contrib

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