thermal analysis results

Dear experts, I have done a simple thermal analysis. It is a rectangle with a circular hole in the middle. Initially the whole setup is in room temperature (20 degC). I keep the heat source in the middle and heat it to 100degC. I expect to see a increase in temp from inside to the outside layer. But unfortunately, contrary to my expectation, in the first sub step itself, the temp near the heat source goes below zero. My guess is it is impossible. Please see attached figure. Where could I have gone wrong?
Any advice regarding this analysis is greatly appreciated!!

Thanks
Lax

Hey kees,
How is it going mate? For some reason, I am not able to attach files. Probably its problem from my side. I am not sure. I have been trying it for a while though. Now I have posted it in at the following location:
www.usaupload.net/d/t1978l846b1

From the figure the inner temp is 100. The outer one is 20. Somewhere in between I get -3.84degC. The temp in the block should be anywhere between 20 and 100 degC. Any explanations/ ideas highly appreciated!

Thanks
Lax<br /><br />Post edited by: Lax, at: 2009/09/19 12:58