ctdlmigrate: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/lib/debug/usr/sbin/ctdlmigrate - from package: citadel-dbg
/usr/sbin/ctdlmigrate - from package: citadel-server

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