dahdi_maint: 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/sbin/dahdi_maint - from package: dahdi

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

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