I'm puzzled! I have just upgraded to Build 11 from Buid 6. When I load
a series previously saved in Build 6, then go to score series, several
of the PY ratings disappear, and I get "Cannot find rating value for
PY/Fireball in rating files" yet it is there! I then have to edit
competitor and re-enter the Class. There seems to be another rating
file, because I get a window that shows the source of the ratings from
the .csv file plus a classes I have used but with no source and no
rating, even though they are in the ratings file. I even get RS800
twice, once with a rating, once without, and it is separately listed
under source in the .csv file.
Fortunatley I don't have a big fleet 
IanF