ok. you may not understand all of this so i apologize in advance if thats the case. Im swamped with work where Im physically located so I cant spend a great deal of time on this.
if you look at your site you may notice that in addition to the formatting problem you describe, your font sizes are off from post to post. I suspect that's being caused by the formatting options youre using inside your posts as you write.
here is a link to validator output for your site's front page:
near the top of that page are some checkboxes. click the "show source" button and then click the 'revalidate" button. That will show you the errors, and give you useful links to where in the source the problem is.
You need to fix those errors first -- if need be, you will have to go back into the posts and edit the posts to correct the error(s).
Once thats done, I suspect your other problem will magically go away.