Before submitting a bug report, check your config for silly errors. Look in your log files for obvious messages that tell you've misconfigured something. Run testparm to check your config file for correct syntax.
Have you looked through Chapter 32, The Samba Checklist ? This is extremely important.
If you include part of a log file with your bug report, then be sure to annotate it with exactly what you were doing on the client at the time and exactly what the results were.