winrar download probs

Hi hope you can help. After successfully downloading 2 games to DS via winrar, I now have the following message whenever I try to download 'can not access save files-remove card and re try'.
Don't know why as I am doing nothing different. Any help appreciated.Cheers - Badge

Try updating your firmware by going to http://www.linfoxdomain.com/ds/.

Cheers for this, much appreciated. Computer has been down for a while so didn't get Chance to sort it out until now.
Once again thanks for your help!