unfortunately since I'm not a dev for windower I can't help you debug any further. I did a quick search of the site for you though and found this:
click me
which seems to be the exact error you are experiencing
one of the posters recommends this thread
click me 2
which may help you out. It appears to be a windower issue so you may want to continue your question there. Essentially what they're suggesting is there is something wrong with the most recent version of windower, and you may need to use an older version for the time being.
Best of luck!