can't install windows on my mac! bootcamp doesn't work!

hello everybody!!!

I tried to install Windows 10 or Windows 8.1 on my iMac but every time I started the installation process with the bootcamp it stops in the middle of downloading of Apple's software to support Windows and write me: "Can't download the software because of a network problem." I know my internet workes properly. Is there a solution for that or any other way to install the windows in a new partition in my mac?

I have an Windows 10 ISO and Windows 8.1 ISO downloaded from Microsoft site and I'm using iMac 21.5 (late 2013)

Thanks for answering!!!

Ariel Kalman