dahdi_span_assignments: 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_span_assignments - from package: dahdi

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

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