tracker-preferences: 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-preferences - from package: tracker-gui

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

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