Alert - "Can't cache image"

[Mike Harris]

I'm getting this alert after selecting the line button in the toolbar.

I'm making flow charts and my diagrams are not that complex, perhaps 50 
total objects or so.

I'm using 2.0.5 (v28) on OS X 10.1.5 ( fully software updated ) dual G4.

After the alert is displayed, screen rendering is failing.  I've tried 
restarting OmniGraffle, however I get the same behavior repeatedly with 
this file. It appears to only happen with this file.  It's a new file I 
just created today, (I've made about 20 or so already today.)

If you need more information, ask for it.

Mike