*BUMP*
I'm having a similar issue on my MacBook running OS 10.6.8. The download (1.4.0.dmg) runs fine; I go to the Downloads folder to find a disk image of 0kb and a .part file of 4Mb. I drag the disk image into Applications, open it from there, and get a "not recognized" error message. If I drag the .part file into Applications and open it from there, I get "There is no application set to open the document 'scribus-1.4.0.dmg.part'." Then a "Download Error" message pops up. Anyone have any ideas? I'm new to the Mac world, and I'd really like to get this working.