You can grab that latest Risk Quantify tarball by going to the SourceForge Risk Quantify project area, and clicking the green "download" button. The source is in a tar gzipped file, so you will need to unzip and untar it as follows:
gunzip -c riskquantify-x.x.tar.gz | tar xvf -
This will extract to the current directory.
Risk Quantify has been stored in SourceForge since August 2000! It was initially in SourceForge's CVS respository, but has since moved to the Subversion respository.
In order to pull the main development trunk of riskquantify, you will want to use the following command:
svn co https://riskquantify.svn.sourceforge.net/svnroot/riskquantify/head/riskquantify riskquantify
This will grab the latest copy of the source code into a directory called "riskquantify".