You can only extract from zip (or other supported xadmaster formats) archives. There's not write access. I have the feeling you're trying to copy *to* the zip archive instead of copying *from* it.
So, just drag files you see in the zip archives and drop them to ram: or so.

And of course, like said above, you can also override the actions as you want, and use unzip or xadunfile instead, if you prefer.