sync-ui: 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/sync-ui - from package: sync-ui

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