http://forum.blockland.us/index.php?topic=173433.0
JVS content is the base for JVS, it has no content in it.You need to download the doors seperately for it to do anything.
Installing things are much easier when you get rtb, I suggest you get RTB, and then download all of the JVS content you can find, then just enable it inside of the "My Mods" Section.
That Didn't help at all. Its still doesent appear on my addon list in blockland
In v20 and up, your Blockland files are now stored in My Documents\Blockland (windows) or /Users/<your username>/Documents/Blockland (macintosh)
When you say install I'm guessing you mean extracted them from the .zip file. Don't do this, just drag the .zip file of the addons into (for windows)documents/blockland/addons and then run blockland.