Protel would have a *.lyt for layout file. Eagle would have a *.brd. Kicad would have a *.pro for project. But this is Design Spark file, as it has *.prj for project. I opened this in DesignSpark and it and has no errors.
DesignSpark is free but closed and server licensed. As good hint about it is that has pretty good import features from other programs. For fresh new designs i think Kicad is better, besides its open source, also i find it better than designspark in many regards.
DesignSpark is free but closed and server licensed. As good hint about it is that has pretty good import features from other programs. For fresh new designs i think Kicad is better, besides its open source, also i find it better than designspark in many regards.