There are several possibilities:
Downloading data requires SVN client on your computer, for example TortoiseSVN. To configure it it is necessary to set address of SVN server, use "svn://www.mlab.cz/home/MLAB/". Annonymous access is read only. If you whish to contribute to the MLAB project contact any of the authors.
WebSVN is Web access to SVN server. You can online browse source and design files or you can download compressed subdirectory (tarball, that is tar+gzip archive). You can use link from main menu WebSVN.
Data can be downloaded from FTP server.