That is the correct key, now open it and it should be working

You need the tool to create the key.bin files (which I hope you still have), it's called "MakeKeyBin"

I beleive the file goes in Private/wii/app/RSBE/pf/stage/adventure

I also beleive that the file is called adventure_common.arc

Happy Birthday Mewtwo 2000! 

Happy Birthday mnsg! 

(btw nice textures, glad to see you decided to post hacks from other games!)

[1.14 MB]

Has the stage select screen has exceeded it's file limit? (1.14 MB)

Here's your file

STGDXCORNERIA

Try using this code as well:
 
[Tracklist Modifier v1.0]
0610F9BC 00000014
60000000 60000000
3C80811A 7C601B78
608447E7 00000000
4A000000 81000000
301A46F8 6D755072
1417DF44 7CE03B78
1417DF4C 7C0400AE
161A47E8 00000060
00000102 03040607
08090A0B 0C0D0E0E
0E0E0E0F 10111213
14151515 16171819
1A1B1C1D 1E1F2D2D
2D202122 23242526
2728290A 2D2D2D2D
2D2D2D2D 2D2D2D2D
0A1A040B 100F1600
11271C06 21101020
1F1F1F1F 1F1F1F1F
1F1F1F1F 1F000000
E0000000 80008000

Also, because your using the file patch code, mu_menumain doesn't work on the file patch code so you'll need to manually put it into the iso through wiiscrubber or use riivolution.

Wiiscrubber

Riivolution

Music names i'm not sure about but I do know that your info.pac file is too large, I think the maximum file size is around 390kb (your above the limit by one kb). You can minimize the file size by shortening some of your music titles.

I use GIMP so i'm not too sure if this is the same for any other image editing tool

You could greyscale the stage preview images by opening your image editing tool and greyscaling images (Image > Mode > Greyscale for GIMP)

Have you made any modifications to your SSS?