Q: I got this error while starting a game... The dialog box has the title "Protection Error". The dialog box says, "A debugger has been detected: unload the debugger and try again" or something similar to this. I don't know what a debugger is! What is going on?
A: This is USUALLY caused by an version of Nero 6, which conflicts with the copy protection authentication system your game uses. If you don't have Nero 6 installed in your system, then I can't help you. Try here instead..

Basically, your game wants to protect itself from hackers and crackers, who uses tools to look into the program's inner functions. Those tools are called debuggers. However, debugger presence can be detected, and program can simply refuse to run if debugger is detected. However, detection is not 100% accurate.

In this case, Nero has a module (specifically, a DirectX video "filter") that somehow triggers this message. And since one of the first things a game does is usually display some sort of logo / animation / movie, this is triggered right away.

There are various other causes for it, such as old version of Divx 5, but those are rather rare nowadays.

You do not need to uninstall Nero, just a tiny portion of it. Follow the steps please...

1) Hit Start button, then select RUN... at the bottom. You'll get the run dialog box.
2) Type in the following EXACTLY as shown below

regsvr32 /u "C:\Program Files\Common Files\Ahead\DSFilter\NeVideo.ax

If you get back a dialog box that says essentially that it is successful, this worked, and try your game now. If you got an error message, you likely didn't type in the above exactly as is, or you don't have Nero installed as originally thought.

Try the game you have problem with, and see if it works now.