Doesn't seem to work properly on my 10.3.9 G4 (I get "b." as described above). Pressing "Run application" brings up the file requester, and when I select an app, your program's window says "<name>.app running" at the bottom. But the program doesn't appear, and after a second or two the window message changes to "App terminated." I tried it with Firefox, Calculator, and Chess, starting all three from the Applications folder, as well as trying to run a shortcut to MaxIDE on the desktop (using a standalone, compiled version of your launcher) - the same result for all.
Just to check, I tried your launcher in Win XP and Win 98, and it ran fine (could run/terminate apps through the window). In Ubuntu 5.10 Linux I could run apps, but not terminate them through the window (they terminated OK manually).
Just to check, I tried your launcher in Win XP and Win 98, and it ran fine (could run/terminate apps through the window). In Ubuntu 5.10 Linux I could run apps, but not terminate them through the window (they terminated OK manually).