[Roy Dennis]

It sounds like it is finding a corrupted file as it always stops after 4200.
It would be a process of elimination to find the file.

Won't be a quick fix but try this: Open your kma folder and move half the files to a tempory holding folder.
Now let it scan the original folder again with only half the files in, then see if Hoster opens or crashes again, if it scans that folder ok then you know the culprit is not in that batch. Now gradually add the files from the tempory folder. From the build database dialog use the rescan button each time taking note of the id's so that if the next batch crashes you know it was in that bunch.

If it crashes after the first 50% try removing more files to the tempory folder then letting it scan until it imports the first lot OK.

I don't know a quick fix the only other way is to examine the songs.mdb file if it got to 4200 and see if you can tell from that what the next song would have been, you would need Microsoft Access for that or you can view it in excel.