you sure its a trunk problem? Based on the searches I have done, the trunk has a mechanism that doesn't allow you to open it unless the top cover is latched - when it is in emergency mode, you need to "push down" on it to actuate the switch to release the trunk mechanism. BMW repair CD says "have a 2nd man push down on both side", although I think you can just push down on the passenger side, and you'll here it "unlatch"
I've been doing a lot of research on the same type of issue, and came across this great site.
Let me know how it goes.