When you encounter that GPX Viewer is crashing, you can help us resolving your issue by locating GPX Viewer crash log file and sending it to us to our e-mail address gpxviewer@vecturagames.com.
To locate GPX Viewer crash log file, you can use some file manager app with which you are familiar. If you didn't used any file manager app, we recommend you using Total Commander app - https://play.google.com/store/apps/details?id=com.ghisler.android.TotalCommander.
To get GPX Viewer crash log file, open your file manager app, in Android file structure navigate to your external files dir (this depends mostly on device, but in most cases it should have path /storage/emulated/0). Next, navigate to directory Android/data/com.vecturagames.android.app.gpxviewer/files. In this directory locate crash_log.txt file and send it to our e-mail address gpxviewer@vecturagames.com as an attachment.