Something wrong adding numbers

Hello All,

I am using VBA in access to perform some calculations. There is a
particular sumation that is wrong (barely).

this code is withing a loop.

        TDist = TDist + TempDist

Both TDist and TempDist are declared as doubles:

    Dim TDist As Double
    Dim TempDist As Double

After looping through 7000+ iterations the following addition produces
this result
These are the exact values of the variables:
TDist = 6388254.993
TempDist = 36.334

 When:      TDist = TDist + TempDist

TDist = 6388291.32699999

TDist is suppose to be 6388291.327

Although the difference is negligable and a simple Format would fix
it. I noticed it only happened here, I can't reproduce it in the
Immediate window.

I am worried if it's going to generate a much larger error. And when
its ac***ulative, it tends to grow errors like this, especially when
running 200k iterations or more.

Is this something anybody has experienced?
Is there a solution to prevent this error?
Or is this just some highly unlikely situation that occured to me for
a very remote and Highly Unlikely combination of data? (Sounds alot
like Douglas Adams)

- GL