tophat: 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/tophat - from package: tophat

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

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