You will need a tool to unzip these downloads, and we suggest you use the free program jZip. All files in the archives were zipped using jZip, whereas most of the products in the monthly download additions were zipped using 7-Zip. jZip will open either and is actually an easier to use version of 7-Zip (in our opinion), not to mention we have had some problems opening up jZip files with 7-Zip.  Although we have never had any problems with jZip, there are apparently some corrupted versions so we highly suggest you get it at their home page which is this site.