dotforward: 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/dotforward - from package: courier-mta

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