Hi NIsha
It might be related to OBN setup for Performing an Object Based Navigation (OBN) call in SourceRole to a target iView in the portal.
If the issue does not fix for you then you may have to raise a note to SAP but this has got something to do with the OBN setup Try to copy again the role without deleting the Navigation folder...which you will find in OBN and then logging off and loggin in again
Define System Landscape -> at backend system column "System Alias for POWL Navigaton" specified "SAP_SRM" (same system name as defined in iView).
Check the note below :
1386141 - There is no iView available for system "XYZ", object "ABC".
If nothing helps ,. you may have to raise a note to SAP
Regards
Vinita