I'm not exactly sure if it is a problem with the disk or not, but that error message means it was unable to instantiate a type of that class. That can normally occur if it is either unable to find the file requested, or it is not in the correct format. From what you stated about your friend copying the game over to your system, I'm not exactly sure how that was set up, but there is a possibility that it was not transferred correctly for your machine. I would recommend that you go ahead and contact Black Isle for CD replacement as you will probably need it. The other option is to attempt a CD copy using CD Burner technology, but you will need hacker software, because Black Isle uses hidden file/sector technology on their burns. A lot of Burner software will not see this and will not copy it correctly and it will either come up with errors, or it will tell you to insert whatever CD it is supposed to be.
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Death Waits 4 U ALL