Can it be that you didn't reboot the server betwen the uninstallation and the installation that followed?
The thing is, the uninstaller usually can't delete the program files because they are locked. Therefore, instead of deleting the files directly, it tells the OS to delete the files on next reboot.
The problem is that if you reinstall the product before performing the reboot, it install completes OK but next time you reboot the OS deletes the new files (because it was told to do so by the uninstaller)!
Does that make sense?
Cheers
Vlk