tcxmlcheck: 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/tcxmlcheck - from package: transcode

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

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