exp: 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/exp - from package: alliance

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

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