expect_multixterm: 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/expect_multixterm - from package: expect

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

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