The WebAssist installer ran to completion after opening a php page - downloaded, installed, restarted DW.
Still the same issue with the Unique Database Value - box flashes on screen then vanishes.
I had a similar problem with my PC at home with exactly the same configuration as for my PC at work, but all DataBridge windows were affected like this - nothing opened. I removed Databridge from Ext Manager then reinstalled DB 1.2.1 - all fixed.
Could it be the installers & uninstallers in the Configuration/Floaters & /Commands folders?
I have the Oct 2014 versions.