dnswasher: 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 CentOS possible default full paths are:

/usr/bin/dnswasher - from package: pdns-tools

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/dnswasher - from package: pdns-server

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

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