dsync: 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/dsync - from package: dovecot

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

On Debian possible default full paths are:

/usr/bin/dsync - from package: dovecot-core

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

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