If you are using Firefox you will have problems submitting! Usually it bombs out with some error while you are trying to submit. They hit me with an email last evening about not getting the entire submission I had done with no errors around noon saying I was required to use IE per my original contract (like I really review the agreement every time I submit a survey to all the companies I work), and if I did not resubmit using IE I would lose my commission.
The first time they refuse to pay me for my work because their programmers aren't competent enough to be compatible with Firefox will be the last time! If they can detect that I used Firefox to send me the email they can at least tell me about it when I am trying to submit, not wait till I have finished and then threaten to not pay me. At the very least they could put a reminder on the submission page not to use Firefox along with their dire warnings about cheating.
Not only that, they want you to use a very old version of IE.