The white blank squares can be of two types
One is that they are unselectable. This probably means that you don't have a frames.txt file inside your set.
Other is that you don't see the images but it appears like you can select the white cells. This probably means that the names of files for the frames are not like they are in frames.txt file.
Both cases are strange, though, since you downloaded the frames from coquina daily and they are good.