At the end of step 7 of the installation process, there is an error displayed:
Error executing
/bin/chmod a+x your_path_to_jbds/JBoss Developer Studio.app/Contents/MacOS/jbdevstudio
This fails the installation.
When you click OK, you get: The installation was not complete.
From the error message it's not clear whether it could be the empty spaces in the path.