I have disabled the preview, but the error is still there.
When I look into the field settings I see that the first two fields is set to display as datepicker (which is correct in this case). If I change them to text, I'm able to have my insert and update page created.
When I reopen my preset and set the two fields to display as datepicker again, I get a new error message when the wizzard generates my pages:
While executing timer in WA_SiteTools_progressV2.htm (see attachment). The wizzards hangs on the Insert Page and I can't get any further.
So I believe it has something to do with the datepicker fields.