Graph Not displaying

I have a rather odd problem that has shown up recently (I think since
the 3.6.1 update) when I go to graph results of a search I get a page
that show’s the query, a question mark for the image, and then a
table of the results.

I am having a really hard time troubleshooting it because I am seeing
nothing in rt’s log, or apache’s log to indicate an error or a file
not found.

Has anyone else encountered this or can someone point me in the right
direction to troubleshoot this problem more.

I can send a screenshot of the page if needed.

Shawn Plummer
Systems Manager
CIT SUNY Geneseo
"The mind can make substance, and people planets of its own with
beings brighter than have been, and give a breath to forms which can
outlive all flesh." -Lord Byron