Errors: "Duplicate invocation" and can't find dll's

[Angus Veitch <s368121 at student dot uq dot edu dot au>]

I have just installed the X components of Cygwin and am hoping to 
eventually connect with XDMCP to my Linux machine.  But I'm having some 
serious teething problems.

First, XWin seems to be having difficulty finding the dlls.  If I run 
"XWin -query [computer name]" I First I get an error message saying that 
it can't find cygwin1.dll.  If I copy that dll file from the cygwin\bin\ 
directory into C:\cygwin\usr\X11R6\bin, the error message changes to 
another dll.  If I copy that dll to the X11R6\bin directory, it moves 
onto yet another one that it can't find.

If I run "startxwin.bat" instead, I don't get the dll error.  But when I 
try to run startx, I get:

> winCheckDisplayNumber - Cygwin/X is already running on display 0
>
> Fatal server error:
> InitOutput - Duplicate invocation on display number: 0.  Exiting.


If I try "startxdmcp.bat", I get a similar result:

> mkdir: Cannot create /tmp/.X11-unix with root ownership
> winCheckDisplayNumber - Cygwin/X is already running on display 0
>
> Fatal server error:
> InitOutput - Duplicate invocation on display number: 0.  Exiting.


The supposed cause of this error is that I am running two sessions of 
XWin, but that is simply not the case.  I get the same results if I add 
:1 to the batch files.

Any suggestions?

PS.
This may be relevant: When I installed Cygwin/X, selected all of the X 
components, rather than just the ones that are automatically selected by 
the x-org base package or whatever it was called.  Is this bad?