(Click here for the long version of the argument.)
The Experience Requirement says that the impact of our well-being of some state of the world is entirely determined by features of the world the subject is conscious of, more formally:
if X is a state of the world, and X is good/bad for A, and the (dis)value of X for A derives from P being the case, and if P being the case is not a mental state of A, X must include A's experience of P being the case. Consider the following EXAMPLE:
Suppose that Brutus wants to kill Ceasar; he stabs Ceasar who dies. Immediately after he is put in prison, where he stays 10 years in complete isolation. One year after Caesar's death, Jesus comes and resurrects him.
Intuitively, we would say that Caesar's resurrection deprives Brutus of his main accomplishment in life. (The resurrection seems to undo the killing, or whatever good thing was achieved through it.) So a theory that acknowledges the prudential value of accomplishments cannot exclude the relevance of the resurrection. On the other hand the Experience Requirement says that the resurrection cannot make Brutus' life worse because it lies outside his experience.
In general, what we may call the "success" of an agent's action lies outside the scope of prudential values constrained by the Experience Requirement. By "success" I mean what it is in virtue of that an action fulfils the goal set by the agent in doing that action.In general, facts beside those the agent is conscious of determine the success of an action. According to the Experience Requirement, those facts cannot influence an agent's well-being, which implies that success cannot influence a subject's well-being (as success is determined by those facts.)
Since success is not an optional feature of accomplishments, and since success is excluded by the experience requirement, a view of prudential good that endorses the experience requirement must exclude accomplishments from the list of things that are intrinsically good for a subject's life.