Ramfade you mentioned you have removed the preferences and cache. Can you please confirm if you have completed the steps listed in Solution 1 of Troubleshoot Adobe Download Assistant - http://helpx.adobe.com/creative-suite/kb/troubleshoot-download-assistant.html#main_Solutio n_1.
I ran into this issue when a download was interrupted unexpectedly. Once I completed the steps in solution 1 and reinitiated the download I was able to download the trial successfully.
You might also want to try a wired connection or a different Internet connection while trying to download. Perhaps there is a server between you and the download server which is causing your difficulties at the moment.
Jeff - Thanks for trying to help. I did complete step 1 with no change in symptoms. I kept getting the SAME CRC CHECKSUM (in Disk Utility) with each download:
$68976E38, expected $811480B9
The solution that I couldn't find in the forums was to type this command in Terminal:
> defaults write com.apple.frameworks.diskimages skip-verify -bool YES
That allowed me to mount the disk image and install Photoshop without a hitch.
Thanks to Sumi in Live Chat for this command!