[Roy Dennis]

It sounds like you have a number of duplicated Book id's or Disc id.
When you add the other folders if a Disc Id or Book id in the other folder is the same as the one already imported it tends to over wright the existing which might be a completely different title.
Do you add songs to the data base using different computers then copy those to the other computer ?
If so this can lead to duplicated file problems.
Also when you Add folders to the list of folders that have files in that have been previously indexed it is best to not have any of the buttons for "Song types to index" selected, then it will only add the files that were previously indexed. If you have some files in that folder that were not previously indexed it could allocate an id to it not knowing that that id is already allocated to a file in one of the other folders not yet added to the list.
Once all the folders are in the list then select the type to index buttons and rescan the folder.
It's too late now to use the above but remember for future reference.

Try this first, in the rebuild database dialog there is a Merge Duplicates button, is it greyed out ?
If not press that and see if that re-imports your songs with fresh Id's.

If it is greyed out have you tried selecting the rebuild database button ?After the rebuild it may report that you have so many duplicated files and ask if you want to merge, if it does select to merge.

If after the above you are still missing files report back.
Let us know which version of Hoster your using and if you have kma types as well as kmh.