tcptrace: 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/tcptrace - from package: tcptrace

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

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