I must be missing something here..I have a visualforce page, that enables a user to create a Campaign - I have a pageblock/section with the Campaign Fields, including name, and Name is marked required. I click a button, and if the name field for Campaign is blank, I get this error:
System.FinalException: SObject row does not allow errors

In the logs, the line before my error is a VF Page Message "You Must Enter a Value", but instead of throwing the error back to the user, the next line is:
EXCEPTION_THROWN [EXTERNAL]|System.FinalException: SObject row does not allow errors

And the thing is, if I remove all code in the pagereference call in the controller, and just return null, it still gives the error, but as far as I can tell, I am not writing anything to the database?