Thanks, my faul. I will try mentioned subversion repository, because it seems that it was just missing required SocketPlugin, not build from web sources file.
Jan
You should be able to build with the most up to date sources from the Subversion repository at squeak.vm.org, along with the latest VMMaker on SqueakMap.
I don't know the cause of the problem that you are seeing, but you can probably get a better idea of what is going wrong by running your VM under a debugger. If it turns out to be something specifically related to 64-bitness, there is now a "Squeak 64 bit" category on Mantis for tracking such things.
Dave