I am also facing the same problem. Can anyone help with Quark 8.1?
The latest version of QuarkXPress 8 is 8.5.1 Update your software (it's free!) and try again. It is recommended to always update the softwares to the latest versions because they just fix bugs and issues and also may carry new features. HTH.
Can you determine what kind of picture leads to that issue? I suppose it doesn't occur every time with any picture, does it?
Is the picture located on a distant disk? (server, other partition, external drive?) Or is the XPress file you're on located on a distant disk?