xnec2c: 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 CentOS possible default full paths are:

/usr/bin/xnec2c - from package: xnec2c

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/xnec2c - from package: xnec2c

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

Error in other languages:
xnec2c: bevel nie gevind nie
xnec2c: comandă negăsită
xnec2c: comando não encontrado
xnec2c: commande introuvable
xnec2c: command not found
xnec2c: käsku ei ole
xnec2c: không tìm thấy lệnh
xnec2c: komanda nerasta
xnec2c: Kommando nicht gefunden.
xnec2c: kommandot finns inte
xnec2c: komut yok
xnec2c: nie znaleziono polecenia
xnec2c: níor aimsíodh an t-ordú
xnec2c: no se encontró la orden
xnec2c: no s'ha trobat l'ordre
xnec2c: opdracht niet gevonden
xnec2c: parancs nem található
xnec2c: perintah tidak ditemukan
xnec2c: príkaz nenájdený
xnec2c: příkaz nenalezen
xnec2c: команда не найдена
xnec2c: командата не е открита
xnec2c: 命令找不到
xnec2c: コマンドが見つかりません