Hi,
The URL you have provided is using "Cart Variant" type custom field.
Here is the screenshot from the backend:
Attachment ScreenShot2013-01-10at1.09.58PM.png not found
Especially, make sure the "layout position" field is blank.
And this screenshot is from the product page, (after the custom fields are added to product.)
Attachment ScreenShot2013-01-10at1.12.07PM.png not found
Forum Support.
Regards.