The reason nobody's helping you is that there is no fix for that bug right now
I've had the same problem before with ver. 2.3. If I exited the software, then re-loaded it and re-synced, it would eventually get all the files to the device. I still don't know why it did that. I've only tried 2.5 once, but so far it seems to be better in that area.
Despite the efforts to help by the moderators here, I fail to see why MS had to inflict this on us. Heck, MS owns the drag-and-drop interface of Windows, which is all we needed in the first place.