It happens when the minimum requirement of hardware(RAM) is not provided or may be Oracle Virtual box isn't compatible to install windows 10 as it is latest OS.
May be Oracle virtual box require a latest update to fix this issue.
Try this may work: To avoid error, make sure that you provide at least 2 GB of RAM if OS is 64 Bit or 1 GB of RAM if 32 Bit And also provide at least 2 Core of your processor.
If still getting error, I recommend you to install windows 10 in VMware workstation which I personally used to install and successfully installed.
Hope this information useful for you.