Please copy 'moonshl2.nds' and '/moonshl2' folder onto the root folder of MicroSD, and start 'moonshl2.nds'.
I did this and didn't get any error.
Try using AKAIO.
Try formating your SD with panasonic formater.
Try this also, from AKAIO wiki
QUOTEIf the Moonshell 2 loading screen freezes on the error message, check the moonshl2 directory for a text file called logbuf.txt. If you see it, delete it, then try loading Moonshell 2 again