Is the file d:\PingFederate\PingIISAgent.evtx readable if you edit it?
If not then it is in proprietary format.
Sounds like you are trying to read events? You probably need to enable logging from the PING system. You may want to enable logging such as :
Administrator Audit Logging
Runtime Transaction Logging
Security Audit Logging
Which is documented here on Ping's website. http://documentation.pingidentity.com/display/PF610/Managing+Log+Files
The logs are stored by default in the /pingfederate/log directory and end in *.log not evtx.