A few weird errors

[AlexBlom]

G'day Zen Community,

I am putting the finishing touches on www.headsonic.com.au

The site is showing a few weird errors:

1) At time the Footer is not always loading
2) Sometimes when clicking side product links (eg headphones) it loads a blank screen in the white area instead of a product list like normal (appears to happen 25% of the time).
3) At times, it seems that the white area is pushed to the side at random (once again, about 25% of the time) (see image)

I am unsure if these are all possibly linked with something not loading entirely? I just performed a full upgrade of Zen - so I know every file is in there and fine. Any ideas?

THankyou for all the help- Alex

***huge screenshot deleted***