logtop: 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/logtop - from package: logtop

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

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