It seems that you are getting the interface to appear correctly but it is just not wanting to proceed after this. Do you get an error anytime after the interface opens?
This looks like you might be experiencing a problem with the preview. As a test of this open your DW and before you use the tools go to Edit > WebAssist Preferences. In here select preview and disable it. Once you have done this give it a try again to see if you get any further along. Please post back and let us know what your result is.