Product Version = NetBeans IDE 6.9 (Build 201006101454)
Operating System = Windows 7 version 6.1 running on x86
Java; VM; Vendor = 1.6.0_20
Runtime = Java HotSpot(TM) Client VM 16.3-b01

I suspect this was triggered by importing settings that were saved on a dual monitor system.  When I tried to open the options dialog it appeared as if nothing happened.  Checking messages.log I noticed that there were messages that read:
WARNING [org.netbeans.api.options.OptionsDisplayer]: Options Dialog is opened

I exited NetBeans and tried again with the saem result, but this time I pressed Alt-Space immediately after selecting the Options menu item.. and then I could select "Move" (via keyboard) from the pop-up menu that appeared at the left of the screen.  After selecting the Move item with the keyboard and tapping the cursor keys, the mouse could be used to position the options window on the screen.  It had opened off to the left of the display area.  That is where my second monitor would be in the system that I exported the settings from.  I must have saved the exported the settings while the options dialog was on my second monitor and ass a result that is where it was opening after I had imported the settings on my single-monitor system.