Stats graph is missing on Site Stats

I have lost the graph, showing traffic, in my site stats. In place, in the box were the graph normally is, is a bar containing code. Can’t read the entire code asit goes beyond the edges of the bos and it won’t let me scroll through it. Any ideas what is wrong or how to fix it? It seemx to have happened right about the time I upgraded my All-in-one SEO but I can’t be completely sure of that.