It seems DirectConnect won't run under Snow Leopard. I've just encountered this problem myself; I've only had Snow Leopard installed for a couple of weeks and I just tried to import an IGES file... no-go! I've tried reinstalling Alias 2010 to see if that would solve the problem, but it didn't. I even tried a custom install to try and only install DirectConnect, but the DirectConnect application was greyed out.
I know I didn't have this problem when I was running Leopard, so I will downgrade in the next couple of days and reinstall Alias 2010. I think that is the only solution to this problem. At least until Autodesk releases a version of DirectConnect that is compatible with Snow Leopard... but that could be months away.