Theme or wordpress rendering gaps in single posts

for some reason i keep getting inch and a half gaps of nothing in my single posts, and each time you refresh the page it puts the gap in a different spot. the gaps are not there in the index page, only in the single post pages.

i tried a different them and they were still there. do i need to do something in the coding when i create a new post?

please help! CLICK HERE to see.

Thank you in advance!