dacsexpr: 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/dacsexpr - from package: dacs

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

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