I have a similar problem like that except that it READS my SD card but has a hard time loading th hacks correctly, i always gotta take out and insert the SD card everytime until it lods everything correctly. It even says its "Locked" when it really isn't

I think its something wrong with the Wii though and i had this problem ever since. No way to fix it as far as i know. I've searched everywhere for an answer and no luck.
I just rely on my USB device now, but loads a little slow with Riivolution, but worth it in the end.