Characteristics:
- The X process is running at 99% of CPU.
- There is no related lines in log files
I had a similar issue when using Acrobat5 plugin for mozilla. Once the plugin was launched by clicking on a PDF file, X process went berserk at 99%. Once the PDF file was closed (and the plugin stopped), everything went back to normal.
Then I decided to use ggv for the PDF files. Now something different came up. Once I decided to change some of the preferences in ggv, GConfd went berserk at 80% CPU usage! So I decided to use gv instead and I am happy since then.
The latter might not be related to the former and might not be related to your issues. I am just dropping my 2c here. :-)