I can't find a way of getting rid of this window.
If I use a different user account on the PC (I am running Windows XP Pro, SP2) then the window does not appear. (the problem appears on my daughter's user account.... my account is OK)
I've been able to run java scripts with no problem from my account (I was using chat in g2g last night). Also, my system is clean of spyware etc. as I have just finished disinfecting a nasty case of C2LOP from my system.
I'm sure it must be something really simple (diagnostic style scripting thingy)