Options page update

Hey folks,

I have a plugin that I’ve created that allows the user to insert mathematical graphs into their posts (you can check it out at my blog. I’ve set up an options page for it on the back-end so you can change the colors (and I have a couple of other stylistic things you should be able to change about the graphs, like the size of the graphs, and the location of the script if your website is set up unusually).
However, when a user submits the form, although the information is updated in the WordPress database, and is obviously usable later, there’s no update message sent. I’ve examined the other plugins I have and I’m not sure what mistake I’m making.
I’m putting a copy of the plugin code here

If anyone has any suggestions for me, I’d appreciate it.