pt2to3: 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/pt2to3 - from package: python-tables

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

Error in other languages:
pt2to3: bevel nie gevind nie
pt2to3: comandă negăsită
pt2to3: comando não encontrado
pt2to3: commande introuvable
pt2to3: command not found
pt2to3: käsku ei ole
pt2to3: không tìm thấy lệnh
pt2to3: komanda nerasta
pt2to3: Kommando nicht gefunden.
pt2to3: kommandot finns inte
pt2to3: komut yok
pt2to3: nie znaleziono polecenia
pt2to3: níor aimsíodh an t-ordú
pt2to3: no se encontró la orden
pt2to3: no s'ha trobat l'ordre
pt2to3: opdracht niet gevonden
pt2to3: parancs nem található
pt2to3: perintah tidak ditemukan
pt2to3: príkaz nenájdený
pt2to3: příkaz nenalezen
pt2to3: команда не найдена
pt2to3: командата не е открита
pt2to3: 命令找不到
pt2to3: コマンドが見つかりません