I have a firm believe in the Bible, as for the dating methods, if I seem to make myself look like an expert in that field, I have misled you. I am not an expert in that field, and will not be for a long time, if ever.
Then you should have not stated that Ar-Ar has the same problem. At the least you should have said something like: "Doesn't this have the same problem?"
But in fact you were given the Dating from a Christian perspective reference. Which isn't all that much reading and covers it pretty well. That would have told you that Ar-Ar does not have the same problem. You shouldn't have had to ask.
To simplify things a bit what you should understand is that the creationist sites and "experts" have had plenty of time to learn about this. What you need to understand is that they are deliberately misleading you. I think the technical term for it is "lying".
They deliberately leave out important information about the dating techniques.
The take-away from this is don't trust what you are being told by these guys.