This statement implies a compiler error.

But this statement:

Implies that you can in fact compile the code.

So, the first thing is for you to be more clear in your question.

Now, assuming the first implication is incorrect and all you're really  
seeing is a problem while debugging, my first thought is that you may be  
debugging an optimized build (i.e. "Release" version), in which the  
variable has been optimized away.  I've never run into this with C#, so I  
can't say for sure that this is a real possibility.  But I've seen it in  
other environments, and it seems like the most likely explanation for what  
I _think_ you're describing.

If that doesn't address your question, I suggest doing both of two things:  
try to state your issue more clearly, and create a concise-but-complete  
sample of code that reliably demonstrates the problem (including, of  
course, clear instructions as to what to do with the sample).

"Concise-but-complete" means we can compile the code without any  
addditional effort ("complete") and there's nothing in the code that's not  
absolutely required for demonstrating the issue ("concise").

Pete