acpitail: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/acpitail - from package: acpitail

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