pawserv-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/pawserv-gfortran - from package: cernlib-packlib-gfortran

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

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