[ubuntu] Ubuntu (VBox) Msg: This will delete all programs ... in all other operating systems

I am installing Ububtu in VirtualBox on Windows 7 and I get the message after clicking Install Now button:


This computer has detected no other operating systems.
Erase disk and Install Ubuntu; (checked)
Warning: This will delete all your programs, documents, photos, music, and any other files in any operating system.

I am running VirtualBox and Ubuntu in a Windows 7 environment.

Does the above msg apply only to other operating systems in VirtualBox? 0r will it harm my underlying W7 system?

Thanks
Steve