Mac OS X Server 10.6.5 Combo Updater DMG
MacOSXServerUpdCombo10.6.5.dmg
available on this Apple support page:
http://support.apple.com/kb/DL1326
The download completes at only 25.6 MB, and thus the image obviously fails to mount, both with Safari and Firefox, while it should be 1.12 GB in size, instead.
This should really be fixed, and as soon as possible...
Mac mini Server, Mac OS X (10.6.5), MacBook Pro