Fatal error: Class ‘PEAR’ not found in /home/user1/public_html/go-pear.php

I also had this error and found that KevinD’s fix didn’t work for me, but was able to figure something out based on it. To solve the problem I replaced the line

'Console/Getopt.php'   => 'https://raw.github.com/pear/Console_Getopt/trunk/Console/Getopt.php',

with

'Console/Getopt.php'   => 'https://raw.githubusercontent.com/pear/Console_Getopt/trunk/Console/Getopt.php',

The install completed nearly instantly for me after this change.