paw++.dynamic-gfortran: 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/paw++.dynamic-gfortran - from package: paw-gfortran

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

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