Exception Caught: Cannot load source/destination schema:
Cause: You might probably have an empty namespace for schema file(not schema node) shown in the error above. Usually when we create a schema,respective project name is assigned as namespace by default. But when we add any existing schema which does not have namespace(most likely received from third parties), this issue might occur.
Fix: Easy..Just provide a valid value to namespace property of schema file , build schemas project(if you have seperate project for Schemas which is a good practice indeed) and build map project now.