tracker-tag: 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 Debian possible default full paths are:

/usr/bin/tracker-tag - from package: tracker-utils

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

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