Hello! :) I think i write in the right place. I'll provide you with the information you ask for but anyway.
I run on windows 8.1 -> virtualbox (latest version) and linux kali latest 32bit version (i dont get 64bit options in virtualbox)
and here is a debug log :)
also forgot to mention that the error message is something that the target is unclean and even if i format it or even delete the virtual harddrive and remove kali from the OS list and try installing it again it still sais that the target is unclean. Just tought it may be another error that causes this since the target is indeed clean.