Trouble installing PEAR

I purchased a book called 'Beginning PHP and MySQL for Ecommerce', and am following the tutorial inside. Step two is to install PEAR. I am referred to http://pear.php.net/go-pear . Here are the steps the book lists: 1. Use a web browser to navigate to http://pear.php.net/go-pear. This page contains the source code for a page. Save that code as a file named go-pear-php in your tshirtshop/libs folder, and then run it by loading it into a web browser. 2. Click next, and then in the next screen, click Install. Clicking on the Start Web Frontend of the PEAR Installer >> link in the final screen forwards you to http://localhost/index.php which might not yet exist on your system. -- When I load go-pear.php in my web browser, I get the installation page, and I click to install it, however the installer never gets past 70%. Here is everything I see. Beyond this.. I'm absolutely stuck and terribly confused. Can someone please let me know what I'm missing? What the error messages mean?? > Installation in progress ... 70 % 100 % Downloading PHPUnit-1.2.2.tgz .... Starting installation ... Loading zlib: ok Downloading package: PEAR-stable......ok Downloading package: Archive_Tar-stable....ok Downloading package: Console_Getopt-stable....ok Downloading package: XML_RPC-stable....ok Downloading package: Pager............ok Downloading package: HTML_Template_IT....ok Downloading package: Net_UserAgent_Detect....ok Downloading package: PEAR_Frontend_Web-0.4....ok Bootstrapping: PEAR...................(remote) ok Bootstrapping: Archive_Tar............ Warning: mkdir(C:\WINDOWS\temp/gop1292.tmp\Archive): File exists in C:\tshirtshop\libs\go-pear.php on line 622 (remote) ok Bootstrapping: Console_Getopt......... Warning: mkdir(C:\WINDOWS\temp/gop1292.tmp\Console): File exists in C:\tshirtshop\libs\go-pear.php on line 639 (remote) ok Downloading package: DB...............ok Downloading package: Net_Socket.......ok Downloading package: Net_SMTP.........ok Downloading package: Mail.............ok Downloading package: XML_Parser.......ok Downloading package: PHPUnit..........ok Fatal error: Undefined class name 'pear' in C:\tshirtshop\libs\go-pear.php on line 675