resgen2: 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/resgen2 - from package: mono-devel

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

On Debian possible default full paths are:

/usr/bin/resgen2 - from package: mono-devel

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

Error in other languages:
resgen2: bevel nie gevind nie
resgen2: comandă negăsită
resgen2: comando não encontrado
resgen2: commande introuvable
resgen2: command not found
resgen2: käsku ei ole
resgen2: không tìm thấy lệnh
resgen2: komanda nerasta
resgen2: Kommando nicht gefunden.
resgen2: kommandot finns inte
resgen2: komut yok
resgen2: nie znaleziono polecenia
resgen2: níor aimsíodh an t-ordú
resgen2: no se encontró la orden
resgen2: no s'ha trobat l'ordre
resgen2: opdracht niet gevonden
resgen2: parancs nem található
resgen2: perintah tidak ditemukan
resgen2: príkaz nenájdený
resgen2: příkaz nenalezen
resgen2: команда не найдена
resgen2: командата не е открита
resgen2: 命令找不到
resgen2: コマンドが見つかりません