We use the dynamic roles app engines on a regular basis. We found that if we click the button in the Role page, it calls DYNROLE_PUBL and it doesn't work. However, the app engine DYNROLE works.
The problem is that there's a hidden checkbox field on that PS page ROLE_DYNMEMBER that's labeled "Publish". It's defaulted as checked, which runs the DYNROLE_PUBL when you Execute Rule and dies. We made that field visible so we could uncheck the box, and the DYNROLE app engine runs instead.
(If I remember right, we had to contact Oracle to resolve this issue)