I know this a comparatively ancient thread, but I was searching for an answer, so maybe it will help others...

In an additional twist, while using vista 64 connecting to 10.4.11, I found that I had to change the vista computer name to not contain a hyphen. So, computer name was eric-PC, and the policy NTLMv2 fix made no difference. I changed the name to ericpc (NTLMv2 change applied), and it started working.

For what it's worth...