nucmer2xfig: 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/nucmer2xfig - from package: mummer

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

Error in other languages:
nucmer2xfig: bevel nie gevind nie
nucmer2xfig: comandă negăsită
nucmer2xfig: comando não encontrado
nucmer2xfig: commande introuvable
nucmer2xfig: command not found
nucmer2xfig: käsku ei ole
nucmer2xfig: không tìm thấy lệnh
nucmer2xfig: komanda nerasta
nucmer2xfig: Kommando nicht gefunden.
nucmer2xfig: kommandot finns inte
nucmer2xfig: komut yok
nucmer2xfig: nie znaleziono polecenia
nucmer2xfig: níor aimsíodh an t-ordú
nucmer2xfig: no se encontró la orden
nucmer2xfig: no s'ha trobat l'ordre
nucmer2xfig: opdracht niet gevonden
nucmer2xfig: parancs nem található
nucmer2xfig: perintah tidak ditemukan
nucmer2xfig: príkaz nenájdený
nucmer2xfig: příkaz nenalezen
nucmer2xfig: команда не найдена
nucmer2xfig: командата не е открита
nucmer2xfig: 命令找不到
nucmer2xfig: コマンドが見つかりません