Here is another thread on CIFS issues and potential workarounds

http://forums.iis.net/p/1166043/1937926.aspx

Here is a great thread on how a person reported fixing a problem 500.19 error NetBios command limit and using a UNC based content architecture.

http://forums.iis.net/p/1165964/1937935.aspx

http://download.microsoft.com/download/7/4/f/74fe970d-4a7d-4034-9f5d-02572567e7f7/24_CHAPTER_11_Troubleshooting_IIS_6.0.doc

http://support.microsoft.com/kb/813776

Check out the UNC tag regarding others that have great information.

http://weblogs.asp.net/steveschofield/archive/tags/UNC/default.aspx

Steve Schofield
Microsoft MVP – IIS

Here is the syntax to capture a memory dump using adplus (part of the debugging tools).   FYI if you need to capture a ultra large w3wp process, you will need to increase the ping timeout inside IIS so the dump doesn’t fail.  IIS will detect a ping failure, and recycle before the memory dump has finished writing to disk.  I’ve used this since IIS DebugDiag doesn’t work on 64 bit of windows server 2008.

adplus -hang -p <PID> -o path to file 

http://support.microsoft.com/kb/286350