I got an old qxp file created on a MAC with QuarkXPress.
Is there any way I could open and maybe edit this file on Ubuntu?
I'm afraid you can't. Scribus is the Linux software more akin to QuarkXPress (DTP), and it doesn't import propietary formats (QuarkXPress , Pagemaker)
There is a trial version of QuarkXPress for Windows and Mac. I still haven't found a way to convert the file to another type, but I can at least edit and print it.
Not really a solution, but an alternitive