My guess is that your Chrome Browser recently updated. Often when browsers update these settings are reset to default. I just tested it on Chrome and was able to get in following the steps below (roughly, I just got up and my coffee is still brewing).

When you click on flashchat, your browser should open another window. In the top left is a attention icon, if you click on in it it will tell you that the site might not be secure or something like that, you can either open a list of plugins, (or it was open immediately) look for the flash plug in, in the options you can "Allow always on this site". Click that and the plug in will load.