Major problem importing batch zip files

[D S-Nicholson]

All my songs imported from hdd zips are listed as type " custom assembly"
I imported a number of batches of 99 zips with no problems before upgrading to Hoster v3313.
When I tried to import batch of 99 zips using next book id root# , as soon as importing started the book id root# changed to #1 and the songs replaced the ones originally imported from disc. I cancelled import immediately but had already overwritten first five songs, and had to re-import from original cdg disc.
I have just installed V3.316 and have same problem. I have 99 zips in folder, all listed by title - artist , and when I click on add files button 99 tracks appear in track list window, disc id appears as xyz0358 ( correct number for next batch) and Book ID root 0 ,which changes to 358 ( correct ) when I click next button. I then enter brand ( custom assembly ) and when I click to import , the disc id and book root id both change to 1 and start to overwrite my first hoster files.
URGENT Help greatly appreciated as I have songs requested by regular singers that I need to add to my list.
Cheers
Derek
Madas Karaoke