I found some info which might be interesting.
It freezes/gives an error, everytime you copy a save.
This is normal (Well it isn't but you'll have to live with it ).
So after copying just check your slots for the save file.
It should be there.
//Kontsnor
Yeah it works great but it's the obvious Ds factor you loose from it it's not like playing atari games on atari because Nintendo actually use to give a reason to buy their hardware
I just like game consoles how they were intended to play if they have a unique enough reason to buy them anything else yeah just download emulation for it