No it is extremly unlikely that people had the control previously installed. We have recommended against Firefox at this point and the people who have not been able to do the test has been using Internet explorer.
I have sent you an email with our launch page.
As I think you'll understand the people who have the problems cannot easily communicate what settings they have or if the have IE 6.X or IE 7.X.
The biggest problems right now seems to be:
a.) The script to enter usernames is blocked and people don't see a button below the adress field to override this. I cannot know if people don't see this because it does not exists or because they do not understand it. Could this be due to other blockers such as various "firewalls" spyware destroyers etc. I don't know what types there are around because I never use them myself. However i often find that people have all kinds of stuff installed in their browsers: google toolbar, yahoo toolbar and lots of other stuff. Could something like that interfere and block it?
b.) Many people enter the number and it seem as if everything is installed and then nothing happens. No errors no nothing.
c.) Many people experience crashes when the script is launched. The experiment is launched all right, and i do get a data file with nothing in it since it crashes before the first trial. The first part of my experiment is a instruct element with a html page with instructions in it if this could be any hint as to why it crashes.
Edit:
I have now talked to several people and found out that the problem actually seem to occur before the popup box to enter subject id is shown. That is, people press start and nothing happens. They won't even see that something is blocked. This happens in Internet Explorer and people do not report that they have any unusual settings. The solution seem to be to add the site (as well as millisecond.com) as a "secured location".