As I had guessed that you would suggest that I un-install and then re-install Form Builder, that's what I did.
I knew that I had downloaded only the Beta version of Form Builder, so I was surprised when the Extension Manager reported it to be version 2.0.0.
I uninstalled, re-downloaded, re-installed. Reported the same thing. Although I did notice that in the notes below it does say Build 23. A little confusing though.
Anyway, went back to DW and I was able to open Universal Email. Must have needed to be re-installed for some reason.
PS: this being shown a blank page thing is driving me nuts! Been Using Firefox. Now trying IE.