In the first post of this thread I posted a possible workaround. Did you try to start the application from the installation folder?
However, if 1.2.0.0 works for you, please stay at the stable version. 1.2.0.3 is a beta and may have some issues. However, the difference between 1.2.0.0. and 1.2.0.3 are marginal. I just tweaked some values. Therefore i assume that the issue must be on your system. But I have no clue what it might be...
@All: I'm on vacation for the next 3 weeks. I might be able to read/post but I'm not 100% sure...