oh hai,
Well, at first: Can your card open wood Official...
Second: Make sure that the game and the save file are in the same folder
third: The save extensions for wood are: savedgamename.nds.sav... that makes .nds.sav (OR at wood 1.19 ONLY you can use "savegame.sav ... the .sav extension)
And the last step.. Make sure that your game name and save name are exactly the same... So Mariogame save should be called the same as the game
If all this fails, switch to Wood 1.19 plz.