That is a very common failure the flap mechanism needs to be replaced. It is a pretty involved process from memory. If you follow this link
http://www.pelicanparts.com/techarticles/Porsche-996-997-Carrera/71-BODY-Convertible_Top_Mechanism/71-BODY-Convertible_Top_Mechanism.htm you can look at illustration 6...the flap mounting is BEHIND all that convertible top mechanism.
- Casey