After figuring out the admin privileges issues.. see PM, I re-ran the tests from a normal command prompt and got the Installer to run fine. Here are the results.
Actually, a clarification would be helpful. Try starting it via command-line: go to the directory and do "java -jar FreeSpaceOpenInstaller.jar". Then run it as usual. Now, after the installer is complete, a) does the window close? b) does the program return control to the command prompt (i.e. can you type more commands)? c) is javaw.exe still running in the background?
EDIT: Also, d) could you run "java -version" and tell me what you get? And e) if javaw.exe persists, then does it still persist if you exit the program on the first screen? f) on the screen just before installation? g) if you hit the close button rather than "Finish" on the last screen?
Had to run through a console with admin privileges or the installer complained about not being able to create a temporary folder and couldn't continue. Not sure if this skewed the results or affected the outcome different than just double-clicking on FreeSpaceOpenInstaller.jar (which hasn't ever asked for privileges).
A: Yes
B: No (Command Prompt is stuck at "Page - Install Completed! Ready to move to next page.")
C: Yes
D: java version "1.7.0_51"
Java(TM) SE Runtime Environment (build 1.7.0_51-b13)
Java HotSpot(TM) Client VM (build 24.51-b03, mixed mode, sharing)
E: No
F: No
G: No
The only way I was ever able to get control of the command prompt again is to kill the java task manually.
[attachment deleted by an evil time traveler]