apirst2html: 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/apirst2html - from package: epydoc

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

Error in other languages:
apirst2html: bevel nie gevind nie
apirst2html: comandă negăsită
apirst2html: comando não encontrado
apirst2html: commande introuvable
apirst2html: command not found
apirst2html: käsku ei ole
apirst2html: không tìm thấy lệnh
apirst2html: komanda nerasta
apirst2html: Kommando nicht gefunden.
apirst2html: kommandot finns inte
apirst2html: komut yok
apirst2html: nie znaleziono polecenia
apirst2html: níor aimsíodh an t-ordú
apirst2html: no se encontró la orden
apirst2html: no s'ha trobat l'ordre
apirst2html: opdracht niet gevonden
apirst2html: parancs nem található
apirst2html: perintah tidak ditemukan
apirst2html: príkaz nenájdený
apirst2html: příkaz nenalezen
apirst2html: команда не найдена
apirst2html: командата не е открита
apirst2html: 命令找不到
apirst2html: コマンドが見つかりません