I have experienced this problem on multiple Lenovo laptops (all Thinkpads), multiple versions of Skype, multiple versions of Windows (all 64-bit) and multiple Bluetooth headsets (all Plantronics).
In this case: W510, 16GB RAM, Windows 7 Pro 64-bit, Skype 4.2 and 5.3, Plantronics Voyager Pro
Without Skype running, I can use Fn-F5 to enable BT, power on the BT headset (it auto connects), power off the headset (it auto disconnects), and use Fn-F5 to disable BT. Furthermore, I can do all this multiple times. All seems very robust.
With Skype running, I can do most of these steps and they work fine, I can use the BT headset with Skype, etc. Just one critical thing does not work: If I power off the BT headset while Skype is running then I immediately get an error pop-up and Windows application event log entry indicating that the BtStacker.exe process failed (ie. crashed). From that point on, BT is unusable until I reboot Windows.
It's the Lenovo support BT drivers (created by Broadcom, apparently) that crashes.
QUESTION: Is anyone else experiencing this problem or know of a solution?
I reported the problem to skype when I first encountered it, long ago, but without getting any real attention on it. I just opened another incident and so far there is no indication of a problem within Skype, itself. The concensus if mounting that the root cause is in the Broadcom driver.