Unable to parse Shibboleth Identity Provider configuration file: java.lang.Exception: IdP configuration could not be loaded from FILENAME
Be sure to have the file:// prefix in the web.xml that specifies the path to the idp.xml configuration file, and NOT eg:
...
as that will raise the above Error. Instead try:
<param-value>file:///etc/shibboleth/etc/idp.xml</param-value>