Okay, so let me see if I have got this correct. You used a program called "magicISO" to create an image of your Wii game disc? Unless there is a new method out there( there may well be) this cannot do it.
First off, have you got the CFG loader up and running? if so you Have to plug your HDD into the right hand side USB port (the left wont work)
then open the homebrew channel, open the CFG loader, it will give you a message something like "HDD isn't formatted, would you like to format disc, select yes.( I am presuming that you are using this HDD solely for Wii games. It will do it's thing, then you put your game into the wii, press the "+" button on the wii mote, it will ask if you want to add game to HDD, choose yes, it will then add the game to the HDD. (it will take about 5-10 mins) you then will be able to select it from the CFG loader and it will play.
I hope that makes sense to you, if there is something else you don't understand, just re post here and I will try to help out again.
The reason I requested you to copy and paste your PM here is that if someone else has the same problem, the solution is here, on the open forum.
I can wait to play agian!