[XeTeX] xelatex and tikzpicture

[Mike Maxwell]

I've created some diagrams using the free tool 'dia' (an open source diagramming tool).  In the 
past, I've exported its diagrams as jpegs, and imported them into my Xelatex file as such.  That's 
probably not the optimal way to do it.

Dia will also output a .tex file, which uses the tikz package.  I tried this, using 
\input{<filename>.tex} in my xelatex file (along with the \usepackage{tikz} and 
\usepackage{morewrites}).  I get approximately half a bazillion warnings from xelatex, and while it 
outputs a PDF, the diagram does not appear (there's a mostly blank page).

Here's a subset of the warnings from xelatex:
--------------
** WARNING ** Unknown token "pgfs"
** WARNING ** Interpreting PS code failed!!! Output might be broken!!!
** WARNING ** Interpreting special command ps: (ps:) failed.
** WARNING ** >> at page="67" position="(-4876.72, -16639.2)" (in PDF)
** WARNING ** >> xxx "ps:: pgfs"
** WARNING ** Stack not empty after execution of inline PostScript code.
** WARNING ** >> Your macro package makes some assumption on internal behaviour of DVI drivers.
** WARNING ** >> It may not compatible with dvipdfmx.
** WARNING ** Unknown token "pgfr"
** WARNING ** Interpreting PS code failed!!! Output might be broken!!!
** WARNING ** Interpreting special command ps: (ps:) failed.
** WARNING ** >> at page="67" position="(-4876.72, -16639.2)" (in PDF)
** WARNING ** >> xxx "ps:: pgfr"
** WARNING ** Unknown token "restore"
---------------
I'm guessing the problem is summarized by the warning:
    Your macro package makes some assumption on internal behaviour of DVI drivers.
Is there something I should be doing to make this work with xelatex/ dvipdfmx?  Or is it not 
possible?  (If .tex is not possible, and I'm understanding correctly, I suppose the .png format 
would be better than .jpg.)

I'm using the latest TexLive 2012 version (XeTeX 3.1415926-2.4-0.9998).
-- 
	Mike Maxwell
	maxwell at umiacs.umd.edu
	"My definition of an interesting universe is
	one that has the capacity to study itself."
         --Stephen Eastmond