I wanted to get some files formatted through QuarkXPress

Hello People,
I wanted to get some files formatted through QuarkXPress (R) and failed to receive an error message. It is showing the problem with the resolution. I want to know elaborate description in respect of the problem.
If you know, please let me know in details.
Thanks for the support.

QuarkXPress (R)
One or more of the select picture has a resolution lower than 91 dpi and is limited to a low-resolution display. [10109]
