I am not familiar with "CodeContracts" but I will give this a try.
It may be because you are Dim'ing something, but are dividing it in the same line, so "CodeContracts" may think that, "Oh, this line is Dim'ing something, move on to next line."
By this I mean, that the "CodeContract" is looking for an actual line of code that is just dividing. For example:
result = 5 / 0
Instead of:
result = Divide(5, 0)
This could also just be, the technique in which you are dividing, but keep in mind, I have never worked with "CodeContracts" before, so this may be way off, but hopefully this helps!