Gallery, Mental Training, and HCG Problems.
This issue is happening because the StreamingAssets folder, which is needed for Unity, is missing.
The code tells the game where to look for the files, but since the actual folder isn't there, it can't find anything.
I'm not sure why, but this folder has been missing from the files since version 0.23.1.
If you have version 0.23, you can just copy the folder from there.
If not, you can download the file below and move it to the right place.
ps. I just learned that if a folder only has one file inside it, some compression programs will only zip the file, not the folder itself. I'm sorry to anyone who had trouble with the last download.
To prevent that this time, I've added a dummy file and a readme with simple instructions.
The readme has the same info, but just in case: unzip the file, move the whole folder to ImmortalLoss_Data, and then you can delete the readme file.