Yes, right now that graphs only work in Firefox (maybe others, but definitely not IE). IE doesn’t support the canvas object that is used for the graphs…I’m planning to hire someone to add IE support in a future revision. But I’m not sure how long that will take, and whether we’ll actually be able to afford to make it happen. Worst case scenario, we’ll punt and use GD to generate static graphs for IE (the graphs now are dynamic and when you hover over a spot it provides exact numbers…it’s very cool).
The insecure items warning will be fixed in the next 3.47 release of Virtualmin. It is merely some hard-coded links in the library calling back to the server at MIT where the graphing library originated. The IE problem probably will be another month or so, if it can be fixed at all.