Let me remind you that it is a Java (GPRS) phone and not an Android one.
All the apps like Foliant are stored in an SD card which I insert into the Samsung phone.
Yes, there is plenty of space in that SD card.
Only Foliant is giving me trouble.
Another E-book reader, Albite, which I also have on my SD card is NOT causing any problem and is working fine. I am easily able to add new books into it.
Yes, I tried turning it on and off. That did not work.