You need to have a .LS3 file, and this need to put it in the Data folder.
Then the rebuild should work. The LS3 files are the same (PC and Mac), so you should ask the vendor for the LS# file that you need.

For anyone interested in making their own LS3 files (for styles that they have added)
LS3 files are just text files, you can also make your own...
http://www.pgmusic.com/styledata.htm


Have Fun!
Peter Gannon
PG Music Inc.