Nimbus Look and Feel is not applied correctly all the time

Okay, thanks to your help it seems to be working now.  The theme is displayed correctly every time after launching it 32 times.  To get it working I had to do the following:

1.  I had to set the Look and Feel in the validate method instead of the restored method.
2.  I had to change another one of my modules that has an installer class and move that code from the restored method to the validate method; otherwise I would get an illegalStateException when it tried to display the splash screen.
3.  I had to use my original code that sets the Look and Feel rather than installing it as suggested in the previous post.  If I install it(the normal Nimbus L&F) then it shows up twice in the Options->Appearance->Look And Feel drop down box AND some of my icons have a white border around them as if they are not transparent.

Again, thanks to everyone's help.  I will now create a separate post to deal with allowing the user to switch between the Normal and Dark Nimbus Look and Feels.