I am using Wubi. Do I need to make a separate partition for Ubuntu? The last time I tried this, it made a folder called
root on my drive and I could not access any files on that drive within Ubuntu.
No, if you are using Wubi (the Windows installer) to install Ubuntu in Windows, you don't need to do any repartitioning. Partitioning your drive is only required if you plan on installing Ubuntu alongside Windows via the LiveCD/USB method. Wubi installs Ubuntu in such a way that it is more like a Windows program instead of a standalone OS with its own space.
If you need to access your Windows files in Ubuntu if you installed it using Wubi, see Accessing Windows partition inside Wubi.
For more information on Wubi in general, see here.
you should do it in windows . if you will do it in linux , maybe can be a problem. Disk Manage Windows . after that you can install ubuntu . and you should mount windows disk to ubuntu