Normally google is my friend for these kind of newbie problems, and I'm pretty proud of myself learning as I go without really needing to ask any questions in terms of PHP stuff, but this one's got me stumped. Trying to install a version of PEAR that supersedes my host's copy, which is hideously outdated. Apparently "pear's binary (bin) directory should be in your PATH variable." I don't know what that means or how to edit it, and supplementary to that, wether that will actually solve my problem of an outdated version of pear being on my root server. Any advice in either of these areas would be greatly welcomed, thank you.
Actually, they are talking about the OS's PATH environment variable, not PHP's include path (binaries [bin] are run by the OS, not parsed by PHP) Unfortunately, since you are in a shared hosting environment, you cannot change this environment variable in a permanent fashion. If you do have shell access though, you can modify your .profile file set the PATH variable.
You can use getenv() and putenv() to retrieve and set the PATH variable, but this will be reset on each script run.
That said, you do not need the PATH variables set to use PEAR. If you have a PEAR install on your development computer, you can upload the pear folder onto your host and modify the include_path at runtime to point to your own "install" using set_include_path()
$pearInstallPath = realpath('./pear/packages');
set_include_path('.' . PATH_SEPARATOR . $pearInstallPath);