This plugin is not needed for Linux
as a ppa package is already available.
Administrator permission is needed to write to the gshhs folder on Windows. An updated version on GitHub tests for the necessary permission.
If the plugin fails with a warning about write permissions please close and re-run OpenCPN
as Administrator. The easiest way is to find the opencpn.exe file with Windows Explorer, right-click on the file name and choose 'Run as administrator'.
Perhaps the installer for OpenCPN should give write permission to the /gshhs folder?