I just went through this installing 4.3 on my Vista computer. After many, many hours, here's what I did:
1. I did a complete, clean uninstall of all Blackberry, Roxio and Sonic software (Sonic will interfere with Roxio). This entailed cleaning out registry entries, deleting files from a number of locations and then re-registering ATL.DLL.
Instructions are here
. Make sure that, in addition to scrubbing the Blackberry software, you also delete the Roxio software.
2. I reset all registry permissions using the SUBINACL technique described here
. In case you're worried about doing this, there are identical instructions on Microsoft's website, but I don't have time to look for them now. Registry permission issues seem to have become chronic with the release of Vista SP1 and XP SP3.
4. Download the Desk Manager software for whatever version you're installing. DO NOT RUN IT YET. Extract all the files (using WinZip or something similar) to a temporary folder on your hard drive.
5. Download the Blackberry Device Manager software. Install it.
6. Once it completes, go to the folder to which you extracted the Desk Manager software. Find the SETUP.EXE file. Double-click on it and it will install the Device Manager software and then the Roxio Media Manager.
On my system it installed perfectly using this technique. If, however, you get the "can't find the XXXXX.msi" error message, you'll be able to point the installer to where you extracted the Desk Manager installation software.
This took me, literally, 7 hours to work out, including at least 2 hours on the phone with various techs at RIM -- I finally got someone in Singapore (!!) who really knew what he was doing and got me started on the right track. This technique addresses a number of potential problems and it's hard to say which is responsible for the problem we've been experiencing. However, it does work. Just be patient -- all the steps take time, particularly re-setting registry permissions.
At any rate, I no longer have the Roxio Media Manager issue and everything works.