Dreamweaver website moves in firefox

Hi

I am currently studying IT at college and I am designing a website on dreamweaver but I have created it and it works fine in Internet Explorer but when I open it in Firefox some of the div tags move over to the side. I have used wrapper to keep them from moving about on IE but it doesn't seem to work on Firefox.

Can anyone help me out please, I haven't done a website before so I don't know that much about everything.

Thanks in advance