tkaepa: 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/tkaepa - from package: aegis-tk

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

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