Sonnox Oxford effects blacklisted in Cubase Le4 on Windows 7

I’ve just upgraded to a laptop running Windows 7, and am trying to use several Sonnox Oxford plugins in Cubase Le4. They worked fine when I was running it on XP, but they are blacklisted on my Windows 7 machine, and nothing I have tried changes this. I’ve re-installed the effects several times, deleted the blacklist, moved the .dll files to other locations and added new plugin paths, read numerous forums around the interweb as well as the cubase documentation, but all to no avail. One thing I haven’t ruled out is the plugins themselves not working on Windows 7, but the Sonnox website assures me that they do. There may also be something obvious that I’ve missed. Any ideas and solutions greatly appreciated…