One line is not enough for us to say: "That's it! Right there! See?" with an error like this, because the problem it's reporting is that a variable already exists in the same scope which has the same name - and it can't cope with that!
It's like children: in a classroom it's not unusual to have two or more children with the same first name ("Joe" for example), and most times this can be resolved by using the family name as well: "Joe Brown" and "Joe Smith" removes the confusion as to which child is being referred to.
But within a family you can't do that: if you called all your male children "Joe" then you would confuse the issue every time you tried to get a specific one of them to do something.
C# is the same about scope: you can't have two variables with the same name.
You have done something like this:
public class MyClass
{
public void MyMethod()
{
MyClass MyClass = new MyClass();
while (true)
{
MyClass MyClass = new MyClass();
}
}
}
And the error is being reported on the second definition of the MyClass variable. Just change it's name, and you'll be fine.