Disc Key does not Correspond ERROR?

[Evil Homer]

I have used the search function with no luck so I hope someone can help me?
Why does this error message come up when trying to run a starforce protected game.
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"The Disc Key you entered does not correspond to the disc
in the drive. Make sure you use the correct Disc Key"
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I don't know why it says this because I know the Key is the correct key, I own the game and it's the same key I've used when playing with the original disc, in some cases like with V8 Supercars 2 and Splinter Cell-Chaos Theory, I've had these games well over 12 months and used them with no problems. So what generates this error message when it's still the same game and CD-Key?
I'm trying to run a couple of Starforce 3 games with the new Daemon tools 4 but I still can't get any of them to run, I've unplugged the power and the CD drive cables from the the drives but nothing, nada, zilch and it's pissing me right off.
So if anyone knows how to get around this error message or just how to get DT4 to work with any Starforce games I would greatly appreciate it. Thanks for any help in advance!