I just downloaded the ZIP and dragged the file out to my desktop without an issue...have you tried downloading it again, or maybe the previous version?
I tried downloading it three times before. However on hearing that you had no problems, I had the idea to try it with Internet Explorer instead of Firefox. No problem that way. Tried again with Firefox, still the same error. Strange. Oh well, doesn't matter anymore.
Use the one for the DX48BT2 I did and it works fine NO problems at all.