The WIRED 4 source code lives in a svn (subversion) repository.
To get a copy of the code locally, for compilation, you need to have a subversion client installed, capable of handling the 'svn' schema.
to see if you have such a client. If not, visit the subversion website to install one.
Check out the WIRED 4 code by issueing the command:
svn co svn://svn://svn.freehep.org/svn/wired/trunk wired4
which creates a wired4 subdirectory and puts the latest revision of WIRED 4 in it.