Am also having "access denied" and rejected credentials problems. These are occuring on a network running MS XP-Server-64 and the 64-bit MPICH2 build. The nodes on this network are configured the same way as the nodes on our 32-bit network. Our applications code works fine on 32-bit machines. That code was built with VS.NET_2003. The 64-bit code was build with VS.NET_2005. Both codes use the debug build.
We followed the documentation carefully when we configured the nodes on the 32-bit network. The 64-bit network nodes are configured the same way as the 32-bit nodes. Am presently going over the 64-bit network and MPICH2 documentation with fine-tooth comb together with our tech support people. If we find out what is wrong, we will post the solution here.
If anyone has had experience with 64-bit networked nodes, please join in the discussion.