How can I find the path where a PEAR library is installed to correct it in php.ini?
You can always find where files are on your system using the locate database like this:
However that is just the overall pear package system and the wires that connect it to php, I don't think that includes the entire archive of PEAR projects. It is likely that you need to install specific PEAR packages fro each things you need to do. These will either be in the package repository, or you will need to use the pear installer to fetch them.