I've experienced similar symptoms. Not black, but unresponsive screen.
I've found this in the error log on one of the attempts...
Exception in thread "XpcMessageLoop" java.lang.RuntimeException: Cannot create destination directory: C:\Documents and Settings\SWilliamson\.JxBrowser\xulrunner-version--unknown\xulrunner-windows.zip
at com.teamdev.xpcom.a.b.b.a(Unknown Source)
at com.teamdev.xpcom.a.b.b.a(Unknown Source)
at com.teamdev.xpcom.a.b.a$a.a(Unknown Source)
at com.teamdev.xpcom.a.b.a$a.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at com.teamdev.xpcom.a.b.a.a(Unknown Source)
at com.teamdev.xpcom.a.<init>(Unknown Source)
at com.teamdev.xpcom.b$b.run(Unknown Source)