Need a CNC simulator...

Hi,
Can anybody tell me of a decent free (or cheap) CNC simulator? I
really like the idea of simulating before cutting. I hand code
everything and sometimes its possible to make a mistake.

I've already tried the one from www.cncsimulator.com . Its ok but
the darn thing stops the simulation every time it reaches a G03
command which I use quite frequently. Strangely, G02's work fine.

Would be great if somebody can give me some advice on how to get it
to work with G03's or reccomend some other similer program. Thanks
in advance.

Mark