apertium-interchunk: 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/apertium-interchunk - from package: apertium

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