I have the same issue on my MacBook (Snow Leopard).
Download a fresh 1.4.3 version, when I laugh app nothing appears. Processes is running in activity log, but all I get is the little icon and the menu bar (which does nothing when you click on it).

Weird bug that should have bee sorted out.
Looks like i have to fire up Parallels...shame...Windows... ** CRINGES **