apertium-preprocess-transfer: 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/apertium-preprocess-transfer - from package: apertium

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

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