sindex: 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/sindex - from package: biosquid

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

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