I think there is some sort of code that has to be entered there before a new idea can be added. But the cost is mostly hidden under the "Powered by Idea Informer" bar. This happens in both Firefox 3.6.6 and IE 8.
Today we've implemented other small improvements and it looks like this problem has been resolved as well. At least we can not reproduce it under IE 8. Could you please to check it and, if the problem still exist, provide us with some screenshot?