o que é: PEAR checks

To testando un webmail e o JAWmail resolveu dar uns erros no install.php

PEAR checks
PEAR files
PEAR.php - Missing!
Mail.php - Missing!
DB.php - Missing!
Crypt/HCEMD5.php - Missing!
Net/Socket.php - Missing!

Isto são módulos do Perl ou nada a ver ???

E esteas extensões do PHP, como instala?
PHP extension check
Gettext support - Missing! Sorry, the installation process cannot proceed without this extension.
IMAP - Present!
IMAP 2000 - Present!
MySQL - Present!
XML - Present!
Multi-Byte String Functions - Missing! Sorry, the installation process cannot proceed without this extension.