tcpcopy: 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/tcpcopy - from package: tcpcopy

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

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