IC8 backup freezing

[hatall]

Hi, everybody. I've made a IC8 backup of Finding Nemo and everything works fine, but when i try to watch the movie with the director's commentary it freezes when switching from the commentary to the movie or the other way around (this dvd has a pgc that is only the movie, a pgc with all the commentaries and a pgc that mixes both of them). If i fast forward it when it freezes for just a second or less, it continues playing the rest of that clip without problems until switching. If i only watch the movie or the commentaries everything goes fine.
It works flawlessly in my computer with windvd.
Any hints ?
Thanxs.

[hatall]

I found out what was wrong. I compared both the original and the backup ifo from the problematic pgc and noticed differences in SP/ILVU/DISC/SA. I changed the backup to equal the original and everything is now working fine. Mainly the SP was 'yes' and i changed it to 'no'. But i don't have any idea about the meaning of SP/ILVU/DISC/SA. Anyone knows ?
Thanxs anyway.