Can't access garagegames with firefox

I don't know why it's suddenly doing this, but since a couple of days ago, I can't access garagegames.com using firefox. At first I thought that the server was down or something so I ignored it and tried again at a later time. However, it still didn't work so I tried it with IE and it was working fine. I deleted all my cookies in firefox and cleared the history and suddenly it started working. But since this morning, it's stopped working again and only loads when using IE. Any ideas why it's doing this? I can access all other sites using firefox and I've never had this problem for over a month.
thanks