Hi Vivek,
Have you maintained values in the Rental Price and Price/ Unit fields in the configuration maintained above?
I believe these are what are causing your error.
I did not use settlement when implementing PAM so have not come across this error before although this link will give you some extra information:
http://www.consolut.com/en/s/sap-ides-access/d/s/doc/YV-PAMS145
Hope this helps. Please reward if I have given you any helpful answers during this post.
Dean