OK, I found a few obscure ways to hit that code.
When you change the color, the application notifies anything that depends on the foreground/background color of the change. One of those things is the gradients in the vector tools. Try using a vector tool and changing the fill gradients to something that doesn't depend on the foreground/background colors (like the rainbow preset). But that call happens even with no document open, so it isn't the most likely culprit.
Another thing that gets notified is the text palettes - and they only get hit when a document is open. If they have some corrupt information (like in the default styles) that could create some problems. So you might try trashing the Default Type Styles.psp file from the Photoshop preferences directory. NOTE - just move the file to your desktop, because if it is the cause, I'll need that file for debugging!