mailcross: 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/mailcross - from package: dbacl

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

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