Why does Oscilloscope cause short?
The ground clip on your o-scope is actually tied to ground. it is a hard short and rather low resistance. This means that you are shorting the 3.3 rail to ground with your ground probe.

To fix this there are two options, 


Put the resistor in the return path
so that one side of it is ground.
That way the ground probe does not
hurt it. 
Use two probes, one for
each side of the resistor and use
the math function on your O-Scope.


Let me know if this is not clear. I can add more information.