Hi,
Tried succesfully followings in win xp:
- Opened Device Manager, where seen NOKIA 920 marked with yellow exclamation mark, go to "Update driver" by clicking it, choose install from a list, then mark the option "Don't search, I will install the driver to install", click Next, in list choose Nokia, then you will see "MTP Device" and "Digital Still Camera". Choose "Digital still camera" and press Next.
Have tried several times with MTP driver but no results.
After installing the driver, could see NOKIA 920 in Explorer, transfer files. Looks like MTP driver signature is not compatible with Windows.
All errors relater to Lumia 920 in Device Manager dissapear, could see under Imaging devices later on under Portable devices, my Lumia 920.
So, this is working well now!
Good luck.