The control panel only allows tar.gz to be extracted. if you want to unzip the zip files they are various ways to do that. as for me i use the http://www.net2ftp.com/ to do all my file management work.
its extracts zip files through the file manager.
It has been said before that only .tar.gz archives can be extracted in DA, and that a whole host of utilities can be used to create them. The most popular one is 7zip in which you should tar the files, then gzip them.