As a follow up to your response, we have discussed through email, and I have also posted the full details to the Pega Mesh Collaboration page, as you recommended. Unfortunately, I have not yet received a response in that forum either.
For anyone who reviews this post, I have also put the full content on the Mesh, just search using the same title. I would greatly appreciate any kind of an acknowledgement that my question was submitted.
This exception occur in some process/section such as Create Case and Finish Assginment during JMeter recording on. The exception has not been solved yet, but I have found the solution by turning off JMeter Record on the process that gets the exception and then replaces it by turning on Fiddler Record. And the solution works. So I can get the HTTP Request from JMeter and Fiddler that I need to create Test Plan in JMeter.