Creaking Bar... Help

[tbushnel]

I have a new Dura Ace threaded stem that I put some Profile aero bars on and I have recently developed a creaking noise that seems to be coming from the bar-stem interface. At first I had slippage problems with the bar, but after some light sanding of the contact surfaces of the bar and stem that problem went away, but I am left with the creaking. It is more noticable after I have been riding enough to warm up, so I was thinking maybe this was due to expansion or something.
Any thoughts about cause or cure?
Thanks in advance.
Ted.
:banana: :argue: