Can't play backups with wasabi dx

I have made two backups on verbatim DVD-R's but neither play.
The chip itself seems to be installed successfully.
Both games were burned at 2x speed.
One is a gamecube game; when put in the wii the gamecube logo comes up, but the screen just goes black.
The other is a wii game, but the game logo doesn't even appear :s.
Would appreciate any help that more experienced wasabi users could give.
cheers

Are you on system menu 4.2 or greater?

If so then the chances are you are trying playing the wrong type of backup, PAL on NTSC or vice versa.

Failing that, it's probably just a bad burn, it happens.