dds2index: 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/dds2index - from package: dds2tar

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

Error in other languages:
dds2index: bevel nie gevind nie
dds2index: comandă negăsită
dds2index: comando não encontrado
dds2index: commande introuvable
dds2index: command not found
dds2index: käsku ei ole
dds2index: không tìm thấy lệnh
dds2index: komanda nerasta
dds2index: Kommando nicht gefunden.
dds2index: kommandot finns inte
dds2index: komut yok
dds2index: nie znaleziono polecenia
dds2index: níor aimsíodh an t-ordú
dds2index: no se encontró la orden
dds2index: no s'ha trobat l'ordre
dds2index: opdracht niet gevonden
dds2index: parancs nem található
dds2index: perintah tidak ditemukan
dds2index: príkaz nenájdený
dds2index: příkaz nenalezen
dds2index: команда не найдена
dds2index: командата не е открита
dds2index: 命令找不到
dds2index: コマンドが見つかりません