I have an image in ecw format. When I try to load it in OKMAP, projection is not recognized. I select it manualy (RGF93 / CC46) then I receive a error message "The points are no good to georeferencing...". I also tried to georeference the image with OKMAP, but received the same message after validation of points.
I've downloaded your map and I've made some tests. There might be something in that projection that isn't right. Next week end I'll have time to indagate better.
I've found the problem. The projection "RGF93 / CC46" has X and Y scale factor set to 0 otherwise to 1. Next release I'll solve the problem. For now, if you want, you can edit the file above with a text editor and change the scale factor X and Y from 0 to 1. The file is located at C:\Users\<user>\AppData\Roaming\GianPaoloSaliola\OkMap\<version>\defs\ProjectionPresets.xml. You should change all the strings "<scaleX>0</scaleX>" to "<scaleX>1</scaleX>" and "<scaleY>0</scaleY>" to "<scaleY>1</scaleY>". There aren't spaces and respect uppercase and lowercase.