ace: 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/ace - from package: libace-perl

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

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