Hello Preethi,
the error case is also explained in the IMPORTANT section in the chapter postsignal:

Why the error occurs in your case is difficult to say. There is some slot method being executed actually due to a preceding postsignal operation and new postsignal is recorded exactly for this method. This can lead to an endless signal delivery. Embedded Wizard detects it and suppresses the intent to post again the signal.
Does this description help you to search for the problem?
Can you reproduce the problem in the Prototyper? Trying to search for the error in the target system will be more complicated.
Best regards
Paul Banach