In order to run it without any error you must enter the input values.
1) username is mandatory
2) database name is optional: if null, the procedure returns all the elements over which the user has privileges.
In your case the query will be
select * from GET_CATALOG_EFFECTIVE_PERMISSIONS (input_username : text,input_database_name : text)
If the issue persists and you have a valid support user account, you may raise a support case on the Denodo Support Site so that it can be evaluated by the Denodo Team.
Hope this helps !