tkaenc: 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/tkaenc - from package: aegis-tk

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

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