R4i SDHC V1.4.1 help.

Hey guys, today I just got my new R4i for Christmas, and it worked... for a while.
I put pokemon white on it, and I played it for about 20 minutes. I turned it off to get my dinner, and when I tried to load it, it said "Open DEMOND.SYS error!".
I've been without flashcards for quite some time, so I'm a tad rusty with it... Can you help me, guys?

[color=purple][b]What's DEMOMD.SYS?

Oh, never mind. I got a new SD card. It's playing fine now. :D