Empty Dates Give #ERR

I have a date column that will be empty for some rows. The array I pass to setCellData() contains "" in those cases, but could as easily use null. However, I get the #ERR text. I'm guessing dataToText() doesn't handle this. Is there a way to avoid this behavior?

Thanks.

See http://www.activewidgets.com/javascript.forum.18549.2/date-js-err-problem.html
You can set the error text to "" using format.setErrorText("")