Could you please capture a screen shot of your view when in standard mode (not full screen view) and then post it to the forum.
This will allow us all to see what style and Realtracks you are using and will help greatly in solving your problem.
To do this...
1. Load the song that has the problem style and is not generating properly.
2. Switch to 'standard view' rather than 'full screen view' (on the Windows version of the program, this option is under the Windows menu and has a shortcut CTRL+T).
3. Generate the song (so that any automatic substitutions and/or changes by BIAB are made).
4. Take a screenshot (I'm not sure how to do this on a Mac but it will be possible).
5. Save the screenshot as a jpg.
6. Go to the below link and follow the instructions on how to upload the jpg image to this thread.
http://www.pgmusic.com/forums/ubbthreads.php?ubb=showflat&Number=386690#Post386690Below is an example screenshot of my BIAB in 'standard view' with a song loaded. When you have the problem style and song file loaded, what your computer shows in this view will be very useful to see.
Regards,
Noel