It was an.ISO file and I had space on my HDD, the ISO, I don't have a Wii and my laptop not very powerful to run dolphin.Do you have enough free space on your hard drive?
Is your file ISO or WBFS?
FYI, if WBFS file, the injector script will convert it back to ISO first before injecting, so it will cost you an additional hard drive space, so 8gb + 6gb or so for the completed WUP.
So if your low on hard drive space this could cause issues.
Have you test your modded game in Dolphin emulator or on a real Wii to make sure the game works? If the ISO/WBFS file hasn't been created correctly, this might cause issues as well.