No, the chat room does not need any downloadable software to work it, and, no again, you can't install Adobe Flash on DS. The most likely reason is that the chat room isn't compatibe with the DS, or the page has simply not loaded yet. If you have a slow connection, you will have to be patient with it. Though it is likely to be an internet issue, keep in mind DS' aren't entirely powerful; and were designed for gaming and entertainment, not specifically internet browsing. If you have another internet connencted device, I would suggest using that.