CVS Checkout Weirdness

Hi, I'm new to CVS, which is probably the root of my troubles here. I've checked out the pear code, and used the resultant folder as my include_path. The individual modules are loading fine, but then anything they try to load doesn't. An example: I want to load the XML::RSS module. It loads fine but then croaks trying to load XML::parse.php (XML/parse.php). There is no 'XML' folder in the pear folder. What's there is XML_fo2pdf, XML_RPC, XML_RSS, etc. This is also the way the hierarchy looks when I browse cvs.php.net with a web browser. Is this correct? If so, how are these modules' modules supposed to load? Thanks for any help, doug --