why will one document not load in pages even though others will?
Given your details and background, the answer would have to be:
We don't know. Why doesn't it?
I tried to open a document today that I last edited on Saturday and it will not open, pages just crashes. But all other documents will open.
What version of Pages?
On Mac or iOS?
What is different about the document?
It may astonish you to know that we can't see what you are doing.
Sorry I forgot to say it was on iPad 3, iOS 6.1 and the latest version of pages.
There is nothing different about the document and it has since happened again with another document.
I press it and it just goes back to the home screen.
Retrieving data ...