fortran77: 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:

/var/lib/wims/public_html/bin/fortran77 - from package: wims

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

Error in other languages:
fortran77: bevel nie gevind nie
fortran77: comandă negăsită
fortran77: comando não encontrado
fortran77: commande introuvable
fortran77: command not found
fortran77: käsku ei ole
fortran77: không tìm thấy lệnh
fortran77: komanda nerasta
fortran77: Kommando nicht gefunden.
fortran77: kommandot finns inte
fortran77: komut yok
fortran77: nie znaleziono polecenia
fortran77: níor aimsíodh an t-ordú
fortran77: no se encontró la orden
fortran77: no s'ha trobat l'ordre
fortran77: opdracht niet gevonden
fortran77: parancs nem található
fortran77: perintah tidak ditemukan
fortran77: príkaz nenájdený
fortran77: příkaz nenalezen
fortran77: команда не найдена
fortran77: командата не е открита
fortran77: 命令找不到
fortran77: コマンドが見つかりません