I am having trouble viewing the latex fragments in my emacs window (via C-c C-x C-l).

First, I was getting no output (*Messages* buffer said "Failed to create png file from ..."). I installed AUCTex and that problem went away.

Now, the latex image overlay shows only a part of the image. If I run dvipng.exe on the temporary file, I get multiple warnings similar to the following: 

c:\Programs\MiKTeX 2.8\miktex\bin\dvipng.exe arning: font cmr7 at 400 dpi not found, characters will be left blank

The latex portions appear correctly if I perform a pdf export.

I am using emacs 23.0 on Windows with MiKTeX 2.8 and org version 6.34trans. Curiously, this was all working fine before I upgraded miktex from 2.5 to 2.8 a few months ago, although that may be a red herring.

Any ideas? 

Thanks.

Cheers,
Scott