What version of Quark are you using? I remember something about Quark 6 deleting text/graphics in layouts, but don't remember the remedies. It was something like <Layout> <Duplicate> upon opening the document and THEN saving it, close the document.
Upon re-opening the document, the original <Layout> is corrupted (Text and graphics missing) but the Duplicate document was in tact, then you could delete the corrupt layout and proceed safely. It's been a while since I had to perform these steps (4-5 years) and they may not be the correct steps to take.
But, here is a link to a page that discusses some Quark 6 opening 4 documents...
http://www.macintouch.com/quark06.html
While I couldn't find the remedy I have explained here on that page, there may be more info that you may find useful...
Good Luck!