Compiling PHP

Hi. I am trying to run a module for Mambo CMS to interface with my Audioscrobbler account. It requires the modules mbstring & domxml. Those are not on Dreamhost’s PHP install so I need to compile my own. I am totally lost after look at the info in the KB and at and other sites. Could anyone explain this to me or direct me to a site that doesn’t assume I am an expert at linux? Also what other modules do I install?