youfoundjake - 3:06 am on Sep 15, 2010 (gmt 0)
I have come across this with several sites as well. One of the offices I support uses Sharepoint internally, and after getting the prompt for the first time, which led to an extensive malware and virus scan, and multiple google searches, I determined that name.dll was ok.
Now as far as functionality, I'm not sure what is lost by not installing it. You can always try it, and if you don't like it, remove the addons from your browser.