reindex: 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/reindex - from package: xbase-utils

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

On Debian possible default full paths are:

/usr/bin/reindex - from package: libxbase64-bin

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

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