When asking for advice, there are things that are helpful:
1. please give the name of the version of APP and the operating system you are using, eg Widows XP SP3, V1.4.2
2. since an image trumps a thousand words, one or more screenshots can be added to your posts. See 'upload slots' in the Image Upload panel, below the 'Message' text panel, when you post. Tip: the images will be displayed in the order of their names - I tend to name the first one 0xxxx, the second 1xxx, and so on
3. if you are working with APP as installed then it helps to say you are using the default settings; if you have made changes mention that. (In this case the 'blender' used in the editor and when rendering may well differ. To see details go to Edit | Settings in the main APP window)
Mac OSX 10.5.5, APP V1.4.2 Default settings for edit and render.
That is helpful already, It was unintuitive for me that the edit preview does not represent the stitch. I have made them the same (Not the default). Particularly as I was looking at the preview to determine how well the stitch was going. Even the numbers said it was good.