Try re-downloading AKAIO . That should maybe do the trick . Do NOT update your DSi . If that doesn't work then try this link to "convert" your .sav from No$gba to Acekard 2 .
http://www.shunyweb.info/convert.php
Hmm to my knowledge there isn't a full English translation ROM yet . But yes you can swap the ROMS , but they have to have the same file name .
>Pokemon Black 2 > Pokemon Black 2.sav