Problem with casting form

I am trying to enter a new casting, and as I type, I keep getting thrown back to the casting list page. I should say thrown forward rather than back, as if I hit the back arrow on my browser, I get back to the casting form containing my post, so all is not lost, but this is very annoying as you can imagine! I have tried to figureb out if it is a certain keystroke causing this and have figured that it is the forward or back cursor keys. Every time I hit one of these, it always forwards me to the castings list page.

I am using a Macbook Air (2011/12 model) running Lion and the stock Safari browser - if that helps!

Thanks, Paul