Well, the save type is flash 64k. I am not sure whether it is a save setting problem but you can still try, it costs nothing

So do the following steps exactly:
- Create a new folder
- Put ONLY the emulator and the rom (no other files such as vba.ini or any save files)
- Open the emulator and go to File>Options>Emulator>Save Type>Flash 64k
- Load your rom.
Note: all your previous save state will be lost, don't try to use them or you won't be able to save. You have to start all over again.
Hope it will solve you problem.