I download latest Aspose.Words and use your demo code to test comment function. The code is as below:
Document doc = new Document();
DocumentBuilder builder = new DocumentBuilder(doc);
builder.Write("Some text is added.");
Comment comment = new Comment(doc);
comment.FirstParagraph.Runs.Add(new Run(doc, "Comment text."));
When I tried to save, it threw out an excption.Please help. Thanks.
BTW, I am using 188.8.131.52 on .Net 2.0