Tailgate problem?

[X5_2_OBX]

I swear someone else wrote about this problem here but I just spent a half hour reading through threads *and* I used the search feature and can't find it so I apologize if this is repetitive.

Last evening, the trunk on our 4.8i wouldn't latch. After several attempts, it finally latched. Today, there is a warning light that says that the tailgate it open but when we check it, it's latched.

It's going into the dealer tomorrow but if you have any insight as to what might be causing this, it would be a huge help! Thanks!