When trying to install a PECL modules you are confronted with the following issue:
If installing from the WHM interface, you see no paths are defined.
Module Include Path
Path Path not found.
If installing from the command line, you get the following output:
ERROR: The default config file is not a valid config file or is corrupted.
These symptoms can appear if PECL is unable to get the correct configuration information.
If the file /root/.pearrc file exists and is empty, then you will want to remove or rename that file.
If this did not address your issue, the problem maybe related to another settings. I would recommend looking at the following articles: