The Blancco Drive Eraser based erasure process itself does not require any installed operating system, as Blancco Drive Eraser is operating system independent (i.e. it loads its own operating system when a device is booted from the USB stick).
The "Blancco5Evaluation" software, which is used for creating the bootable USB stick, requires Windows based operating system (Windows XP or newer with USB port and an Internet connection).
Find more information about the system minimum requirements for the Evaluation version from this article.