can't establish Bluetooth connection to my mobile device

Hi!

I'm using Vista Home Premium with an internal Broadcom Bluetooth device.
When I'm trying to send a file to my mobile phone, the phone can be found, I
am asked to set a key for the transmission (on Windows), but then nothing
happens, and I get the error message "The process can't be executed because
the user is not authenticated" (Maybe it's not really that message in
English, I translated it from German) within the file transfer wizzard.

I already tried to reinstall the device drivers, but the problem's still the
same.
I know they are (were) few problems with Bluetooth and Vista.

Do you have any idea how to solve that problem?

Thank you in advance!