samba version

Is there a particular version of samba that runs better than others for ntlm_auth? I have a ubuntu lucid test server that authenticates wireless users fine using ntlm_auth on initial logins, but randomly it will start failing reauth attempts on laptops that have been logged in for a while. I searched through the mailing list archives and someone previously with the same problem downgraded to 3.0.30 to fix it so just curious.