nexp: 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/nexp - from package: netexpect

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

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