Hi Prasanna,
The issue here is that the mainframe application in Citrix is not local to the machine which is running the automation. Blue Prism is trying to make calls to a local PCOM process, but it is not running on the local machine. This is why you are unable to locate the DLL file, and also unable to activate the COM object (ActiveX component).
The way to automate such an application is to either reconfigure the application package to include the missing COM DLL so that Blue Prism can integrate with it locally or to use Surface Automation techniques. To use Surface Automation with Terminal Emulators, refer to:
https://portal.blueprism.com/learning/guides.
Kind Regards,
Sameer Goel