This is clearly an issue, and I can't believe no one has a solution to it.
The thing is, when I play GHWT from the HD, it really can't access the SD-card in a proper way at all.
Say I have no DLC stored anywhere.
I start GHWT and go into the music shop.
I buy a song, it starts downloading.
After it has finished it will ask me for permissions to store the song on the SD-card:
"Allow Guitar Hero to Save add-on content to the SD Card?"
I give the permissions and it starts transferring.
Now right at the end of the transfer there is an error;
"ERROR. 201017: An error occured. Wait awhile and try again. If the same error keeps appearing, visit support.nintendo.com."
Now if I go to Archive (Options -> Archive) in the game it will appear as if the song is stored on both the Wii itself, and the SD-card (despite the previous error). I CAN PLAY the song, however this is because the song is actually stored on the Wii.
Now, if I in Archive try to delete the song, either from the Wii or the SD card, there will be another error. If I go back to the system menu and check the SD card, and the Wii itself, I find that there actually IS NOTHING stored on the SD card, and in the Wii the "Guiter Hero World Tour songs file" is stored (the Archive file). I delete this file from the Wii, and go back in the game. Now GHWT will tell me that there's no Archive-file and it has to be created and so on, and we're back at square 1, with no songs stored on the Wii or the SD card.
If I were to download songs with the GHWT disc inserted, everything would work out just fine, even moving them to the SD card of course. However, if I then would try to play the songs from the game in HD, it would tell me the songs are out of date and need to be re-downloaded.
If anyone wonders, I have the Waninkoko sys menu 4.0E and the cIOS36 rev13b installed.