Bad Downloads?

hi, i'm new to the boards!i downloaded a few games to my microsd / R4, and sometimes my ds can read them, but other times it cannot. i would get an error message like, "cannot read data. turn off power and reinsert game card." this has occurred when i tried downloading professor layton and zelda.does this happen to anyone else? do some games just not work?any advice/comments would be appreciated. thanks!p.s. i'll have to note that i'm pretty computer/tech-lingo illiterate, so please use layman terms when explaining stuff to me. thanks. :)

Seriously, post in the right section, and I think if you look in the right section, you may find the answer.

You will need to update your firmware by downloading the latest from www.linfoxdomain.com/nintendo/ds.