fastcgi_server: 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/sbin/fastcgi_server - from package: rt3

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

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