I, too, have had this trouble. I have a very large set of music files that need to stay on the NAS. I'm using the simpleshare250, too, and love it.
The simpleshare works like an NT4.9 network drive, and *every* other program works just fine with it.
I have had some individual file issues, but neither the log nor the popup window give me enough information to troubleshoot. As I see it, the process should continue until finished, skipping the problem files if there are any, and then report back with a list of problem files.
I don't want to sift through 50kilotracks directory by directory.
My hardware is new and functioning brilliantly. The NAS is new as well and upgraded. There is something else going on here.