mount_afp: 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/mount_afp - from package: fuse-afp

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

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