You can't do that. We'll have to wait for the release of the Version 2.6B. I think it is advisable to download the latest version [2.6A]. Or maybe the rom is corrupted. Try downloading in other site like 3roms or emuparadise.
Umm.. lemme see..Its says its Version:2.5c i saved in game but no efect i am very new to NDS Emulation so maybe i miss something in the confuguration or im blind and i dont see the "Save Game" and "Load Game" in the Emulator menu Or my Pokemon Diamond is corrupted