This sometimes happens to me, but it has always been fixed by just collapsing/expanding the storage compartment, closing the trunk, and press the opposite button of what I'm trying to do (i.e. If i'm trying to open it, I'd push the close button until it closes and then re-open).
I think in my case it may be related to my trunk release latch mechanism. Sometimes my trunk won't close, so I have to press the trunk release button again for it to "unjam" and then all is well. I get a feeling that most people have some time of "sensor" failure somewhere in the system, and not a pump problem.
Anyone have a Bentley manual?