nsdb.so: 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/lib/aolserver4/bin/nsdb.so - from package: aolserver4-daemon

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

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