I do have component cables, although I don't see why that would make a difference.
Hmm. Is the problem my Japanese Wii?
It could be the dump. I've gotten it from three different sources, although I suppose they could all be from the same original dump. But unless you all dumped it yourselves, I have to assume at least one of you obtained it where I did. There are only so many places to get it.
In the case your tv is'nt compatible with either ntsc or Pal depending your region, you can force video output to use 480P. This however only works using component cables.
480p is the same for both regions, fyi.
Also if you are using the NTSC version of the game, force it's language to english.
I had to force the NTSC dump of the game to NTSC output, whilst I am in the PAL region.
Since I use component on my lcd @ 480p I have no problems.
If you would use the standard leads 480i you would have black screen or black white colors.
This all has to do with the combination of your region Wii and region game + used TV and cables.
Most games fortunately can be forced to using a different video output.
This video information comes directly from the Wii disc and not the Wii itself.
For instance the PAL version of Madworld cannot be forced to PAL 480p since it;s not on the original disc. Pikmin 2 had problems vice versa, so had scarface and a few others.
I am 100% sure mercury meltdown is NOT one of those problem games how ever.