thmsnhl I'm aware that options to create / edit paths in StitchBuddy are rather basic, especially when being compared with vector-based graphic programs like InkScape (the foundation of InkStitch). Actually it is not my intention to offer a competitive editor and I recommend to use 3rd party programs to create more complex shapes. I don't expect StitchBuddy evolving into a full-fledged digitizer, but it rather offers some basic options to add knockdown stitches or simple shapes.
With this being said, the start and end points of open paths are indicated by solid circles. This makes it easier to identify paths which need to be closed before they can be filled. In a future release I consider to close paths automatically if their start and end points are at the same location - even if the path was left open by the external program creating the SVG file.
Regarding the problematic SVG file: The "Generate Stitches" button is disabled when either no Stroke / Fill Type is selected or no path is defined. Importing SVG files might result in no paths depending on the creating program and the import options, please refer to this FAQ article about the different situations and why there is no optimal default setting.