Nope - installing the latest pre-beta worked just fine for me.

The fact that you were not allowed to delete the OCD folder and the dadbapp.exe file during you uninstall attempt, may be the explanation.

If your dabapp.exe file can't be deleted, then it could probably not be overwritten either when you tried to upgrade to the newest pre-beta.

I assume that you have tried to reboot and then delete the OCD file and folder?