I just purchased LR4. I am unable to complete a download of the product. I can start the process, and it will get to anywhere from 50-90% complete and I get a message that the download was "interrupted". When I hit resume, it seems to start randomly at a % complete, sometimes at 50%, then the next time I hit resume it restarts at 20%, all during the same download, but it never completes. I have tried turning off all other processes on my computer, reseting my cable modem, restarting my computer, deleting and restarting the process, but as of yet am unable to get this to finish.
I would recommend trying to download the trial verision at https://www.adobe.com/cfusion/tdrc/index.cfm?product=photoshop_lightro om&promoid&promoid=DTEML and then inputting your serial number after the install process is complete.