I have just started my trial of CurveWorks under CorelDraw 12. I have found a quirk and that is I cannot save my file anytime, but after I have used the CurveWorks curve measurement tools as CorelDraw hangs and I actually lose the contents of the file.
I have refined this issue to this specific point. If I measure a curve with Curveworks and try and save, CorelDraw hangs (lose the whole file contents actually). If I measure a curve with CurveWorks and then do a single 'UNDO' in CorelDraw and save, the file saves normally.