Have you tried any alternatives at all to really determine the problem, whatever it may be?
Like pasting it into another program such as *TextEdit, Bean or iTextExpress* ?
iTextExpress for a start gives you a pageless mode where there are no page margins to cut off extra wide content.
Have you checked if the text has not popped somewhere, but actually is in Pages?
Have you noticed at what point the text has broken off and if there is any special about that?
Have you tried pasting it into a demo of Word to see if it actually is a solution?
The Mac universe does extend beyond Pages and Word:
http://www.freeforum101.com/iworktipsntrick/viewtopic.php?t=47&mforum=iworktipsn trick
Peter