Check my answer to Calick's question on this, it describes how I solved it when I found this issue.
There are certain homebrew features that aren't supported on some firmware versions of flashcards. I'd recommend seeing if you can find an update!
Something like this happened with me. I had to update the firmware to a new version.
I had this issue, I updated the firmware / kernel and to a version that supports homebrew games. Searching your R4 chip's model should come up with some answers.
